二元一次方程和三元一次方程计算题 二元一次方程(三元一次方程)计算题
\u521d\u4e00\u6570\u5b66\u4e8c\u5143\u4e00\u6b21\u65b9\u7a0b\u548c\u4e09\u5143\u4e00\u6b21\u65b9\u7a0b\u8ba1\u7b97\u9898,\u8981\u7b54\u6848\uff0c\u8981\u5bf9\uff0c\u4e00\u517150\u90531\uff0e\u4e8c\u5143\u4e00\u6b21\u65b9\u7a0b4x-3y=12\uff0c\u5f53x=0\uff0c1\uff0c2\uff0c3\u65f6\uff0cy=______\uff0e 2\uff0e\u5728x+3y=3\u4e2d\uff0c\u82e5\u7528x\u8868\u793ay\uff0c\u5219y=______\uff0c\u7528y\u8868\u793ax\uff0c\u5219x=______\uff0e 4\uff0e\u628a\u65b9\u7a0b3(x+5)=5(y-1)+3\u5316\u6210\u4e8c\u5143\u4e00\u6b21\u65b9\u7a0b\u7684\u4e00\u822c\u5f62\u5f0f\u4e3a______\uff0e (1)\u65b9\u7a0by=2x-3\u7684\u89e3\u6709______\uff1b (2)\u65b9\u7a0b3x+2y=1\u7684\u89e3\u6709______\uff1b (3)\u65b9\u7a0by=2x-3\u4e0e3x+2y=1\u7684\u516c\u5171\u89e3\u662f______\uff0e 9\uff0e\u65b9\u7a0bx+y=3\u6709______\u7ec4\u89e3\uff0c\u6709______\u7ec4\u6b63\u6574\u6570\u89e3\uff0c\u5b83\u4eec\u662f______\uff0e 11\uff0e\u5df2\u77e5\u65b9\u7a0b(k2-1)x2+(k+1)x+(k-7)y=k+2\uff0e\u5f53k=______\u65f6\uff0c\u65b9\u7a0b\u4e3a\u4e00\u5143\u4e00\u6b21\u65b9\u7a0b\uff1b\u5f53k=______\u65f6\uff0c\u65b9\u7a0b\u4e3a\u4e8c\u5143\u4e00\u6b21\u65b9\u7a0b\uff0e 12\uff0e\u5bf9\u4e8c\u5143\u4e00\u6b21\u65b9\u7a0b2(5-x)-3(y-2)=10\uff0c\u5f53x=0\u65f6\uff0c\u5219y=______\uff1b\u5f53y=0\u65f6\uff0c\u5219x=______\uff0e 13\uff0e\u65b9\u7a0b2x+y=5\u7684\u6b63\u6574\u6570\u89e3\u662f______\uff0e 14\uff0e\u82e5(4x-3)2+|2y+1|=0\uff0c\u5219x+2=______\uff0e \u7684\u89e3\uff0e \u5f53k\u4e3a______\u65f6\uff0c\u65b9\u7a0b\u7ec4\u6ca1\u6709\u89e3\uff0e ______\uff0e (\u4e8c)\u9009\u62e9 24\uff0e\u5728\u65b9\u7a0b2(x+y)-3(y-x)=3\u4e2d\uff0c\u7528\u542bx\u7684\u4ee3\u6570\u5f0f\u8868\u793ay\uff0c\u5219[ ] A\uff0ey=5x-3\uff1b B\uff0ey=-x-3\uff1b D\uff0ey=-5x-3\uff0e [ ] 26\uff0e\u4e0e\u5df2\u77e5\u4e8c\u5143\u4e00\u6b21\u65b9\u7a0b5x-y=2\u7ec4\u6210\u7684\u65b9\u7a0b\u7ec4\u6709\u65e0\u6570\u591a\u4e2a\u89e3\u7684\u65b9\u7a0b\u662f[ ] A\uff0e10x+2y=4\uff1b B\uff0e4x-y=7\uff1b C\uff0e20x-4y=3\uff1b D\uff0e15x-3y=6\uff0e [ ] A\uff0em=9\uff1b B\uff0em=6\uff1b C\uff0em=-6\uff1b D\uff0em=-9\uff0e 28\uff0e\u82e55x2ym\u4e0e4xn+m-1y\u662f\u540c\u7c7b\u9879\uff0c\u5219m2-n\u7684\u503c\u4e3a [ ] A\uff0e1\uff1b B\uff0e-1\uff1b C\uff0e-3\uff1b D\uff0e\u4ee5\u4e0a\u7b54\u6848\u90fd\u4e0d\u5bf9\uff0e 29\uff0e\u65b9\u7a0b2x+y=9\u5728\u6b63\u6574\u6570\u8303\u56f4\u5185\u7684\u89e3\u6709[ ] A\uff0e1\u4e2a\uff1b B\uff0e2\u4e2a\uff1b C\uff0e3\u4e2a\uff1b D\uff0e4\u4e2a\uff0e [ ] A\uff0e4\uff1b B\uff0e2\uff1b C\uff0e-4\uff1b D\uff0e\u4ee5\u4e0a\u7b54\u6848\u90fd\u4e0d\u5bf9\uff0e \u4e8c\u5143\u4e00\u6b21\u65b9\u7a0b\u7ec4•\u7efc\u5408\u521b\u65b0\u7ec3\u4e60\u9898 \u4e00\u3001\u7efc\u5408\u9898 \u3010Z\uff0c3\uff0c\u4e8c\u3011 \u3010Z\uff0c3\uff0c\u4e8c\u3011 3\uff0e\u5df2\u77e54ax+yb2\u4e0e\uff0da3by\u662f\u540c\u7c7b\u9879\u6c422x\uff0dy\u7684\u503c\uff0e \u3010Z\uff0c3\uff0c\u4e8c\u3011 4\uff0e\u82e5|x\uff0d2|\uff0b(2x\uff0d3y\uff0b5)2=0\uff0c\u6c42x\u548cy\u7684\u503c\uff0e \u3010N\uff0c3\uff0c\u4e09\u3011 5\uff0e\u82e5\u65b9\u7a0b2x2m+3\uff0b3y5n-4=7\u662fx\uff0cy\u7684\u4e8c\u5143\u4e00\u6b21\u65b9\u7a0b\u7ec4\uff0c\u6c42m2\uff0bn\u7684\u503c\uff0e \u3010Z\uff0c3\uff0c\u4e8c\u3011 \u4e8c\u3001\u521b\u65b0\u9898 1\uff0e\u5df2\u77e5x\u548cy\u4e92\u4e3a\u76f8\u53cd\u6570\uff0c\u4e14(x\uff0by\uff0b4)(x\uff0dy)=4\uff0c\u6c42x\u548cy\u7684\u503c\uff0e \u3010N\uff0c4\uff0c\u4e09\u3011 2\uff0e\u6c42\u65b9\u7a0bx\uff0b2y=7\u5728\u81ea\u7136\u6570\u8303\u56f4\u5185\u7684\u89e3\uff0e \u3010N\uff0c4\uff0c\u4e09\u3011 \u4e09\u3001\u4e2d\u8003\u9898 (\u5c71\u4e1c\uff0c95\uff0c3\u5206)\u4e0b\u5217\u7ed3\u8bba\u6b63\u786e\u7684\u662f [ ] \u53c2\u8003\u7b54\u6848\u53ca\u70b9\u62e8 \u4e00\u30011\uff0e\u6240\u8003\u77e5\u8bc6\u70b9\uff1a\u65b9\u7a0b\u7ec4\u7684\u89e3\u53ca\u6c42\u4ee3\u6570\u5f0f\u7684\u503c\uff0e \u2234 2m\uff0b3n=2\u00d72\uff0b3(\uff0d3)=4\uff0d9=\uff0d5\uff0e 2\uff0e\u6240\u8003\u77e5\u8bc6\u70b9\uff1a\u65b9\u7a0b\u7684\u89e3\u53ca\u89e3\u4e00\u5143\u4e00\u6b21\u65b9\u7a0b\uff0e \u89e3\uff1a\u628a x=\uff0d3\uff0cy=\uff0d2\u4ee3\u5165\u65b9\u7a0b\uff0c\u5f97 2(\uff0d3)\uff0d4(\uff0d2)\uff0b2a=3\u89e3\u5173 \u70b9\u62e8\uff1a\u4ee5\u4e0a\u4e24\u9898\u8003\u5bdf\u7684\u77e5\u8bc6\u70b9\u7c7b\u4f3c\uff0c\u5df2\u77e5\u65b9\u7a0b\u7684\u89e3\u65f6\uff0c\u53ea\u8981\u628a\u8fd9\u7ec4\u6570\u4ee3\u5165\u65b9\u7a0b\u6216\u65b9\u7a0b\u7ec4\u5c31\u53ef\u6c42\u51fa\u65b9\u7a0b\u4e2d\u5176\u4ed6\u5b57\u6bcd\u7684\u503c\uff0e 3\uff0e\u6240\u8003\u77e5\u8bc6\u70b9\uff1a\u540c\u7c7b\u9879\u53ca\u89e3\u65b9\u7a0b \u70b9\u62e8\uff1a\u6839\u636e\u540c\u7c7b\u9879\u7684\u5b9a\u4e49\u77e5\uff0c\u76f8\u540c\u5b57\u6bcd\u7684\u6307\u6570\u76f8\u540c\uff0c\u6545\u53ef\u5217\u51fa\u65b9\u7a0b\uff0c\u4ece\u800c\u6c42\u89e3\uff0e 4\uff0e\u6240\u8003\u77e5\u8bc6\u70b9\uff1a\u975e\u8d1f\u6570\u7684\u6027\u8d28\u53ca\u89e3\u7b80\u5355\u7684\u4e8c\u5143\u4e00\u6b21\u65b9\u7a0b\u7ec4\uff0e \u70b9\u62e8\uff1a\u56e0|x\uff0d2|\u22650\uff0c(2x\uff0d3y\uff0b5)2\u22650\uff0c\u6240\u4ee5\uff0c\u5f53\u5b83\u4eec\u7684\u548c\u4e3a\u96f6\uff0c\u8fd9\u4e24\u4e2a\u6570\u90fd\u987b\u662f\u96f6\uff0c\u5373x\uff0d2=0\uff0c2x\uff0d3y\uff0b5=0\uff0e 5\uff0e\u6240\u8003\u77e5\u8bc6\u70b9\uff1a\u4e8c\u5143\u4e00\u6b21\u65b9\u7a0b\u7684\u5b9a\u4e49\uff0e \u89e3\uff1a\u7531\u9898\u610f\u77e5 \u70b9\u62e8\uff1a\u4ece\u4e8c\u5143\u4e00\u6b21\u65b9\u7a0b\u7684\u5b9a\u4e49\u77e5\uff0c\u672a\u77e5\u9879\u7684\u6307\u6570\u4e3a 1\uff0c\u7531\u6b64\u5f97\u5230 2m\uff0b3=1\uff0c 5n\uff0d4=1\uff0e \u4e8c\u30011\uff0e\u6240\u8003\u77e5\u8bc6\u70b9\uff1a\u76f8\u53cd\u6570\u7684\u610f\u4e49\u53ca\u89e3\u7b80\u5355\u7684\u4e8c\u5143\u4e00\u6b21\u65b9\u7a0b\u7ec4\uff0e \u89e3\uff1a\u7531\u9898\u610f\uff0c\u5f97x\uff0by=0\uff0c \u53c8\u2235(x\uff0by\uff0b4)(x\uff0dy)=4 \u2234 4(x\uff0dy)=4 \u5373x\uff0dy=1 2\uff0e\u6240\u8003\u77e5\u8bc6\u70b9\uff1a\u4e8c\u5143\u4e00\u6b21\u65b9\u7a0b\u7684\u81ea\u7136\u6570\u89e3\uff0e \u89e3\uff1a\u628a\u65b9\u7a0bx\uff0b2y=7\u53d8\u5f62\uff0c\u5f97x=7\uff0d2y \u4ee4y=1\uff0c2\uff0c3\uff0c4\u2026\u2026\uff0c\u5219x=5\uff0c3\uff0c1\uff0c\uff0d11) 66x+17y=3967 25x+y=1200 \u7b54\u6848\uff1ax=48 y=47 (2) 18x+23y=2303 74x-y=1998 \u7b54\u6848\uff1ax=27 y=79 (3) 44x+90y=7796 44x+y=3476 \u7b54\u6848\uff1ax=79 y=48 (4) 76x-66y=4082 30x-y=2940 \u7b54\u6848\uff1ax=98 y=51 (5) 67x+54y=8546 71x-y=5680 \u7b54\u6848\uff1ax=80 y=59 (6) 42x-95y=-1410 21x-y=1575 \u7b54\u6848\uff1ax=75 y=48 (7) 47x-40y=853 34x-y=2006 \u7b54\u6848\uff1ax=59 y=48 (8) 19x-32y=-1786 75x+y=4950 \u7b54\u6848\uff1ax=66 y=95 (9) 97x+24y=7202 58x-y=2900 \u7b54\u6848\uff1ax=50 y=98 (10) 42x+85y=6362 63x-y=1638 \u7b54\u6848\uff1ax=26 y=62 (11) 85x-92y=-2518 27x-y=486 \u7b54\u6848\uff1ax=18 y=44 (12) 79x+40y=2419 56x-y=1176 \u7b54\u6848\uff1ax=21 y=19 (13) 80x-87y=2156 22x-y=880 \u7b54\u6848\uff1ax=40 y=12 (14) 32x+62y=5134 57x+y=2850 \u7b54\u6848\uff1ax=50 y=57 (15) 83x-49y=82 59x+y=2183 \u7b54\u6848\uff1ax=37 y=61 (16) 91x+70y=5845 95x-y=4275 \u7b54\u6848\uff1ax=45 y=25 (17) 29x+44y=5281 88x-y=3608 \u7b54\u6848\uff1ax=41 y=93 (18) 25x-95y=-4355 40x-y=2000 \u7b54\u6848\uff1ax=50 y=59 (19) 54x+68y=3284 78x+y=1404 \u7b54\u6848\uff1ax=18 y=34 (20) 70x+13y=3520 52x+y=2132 \u7b54\u6848\uff1ax=41 y=50 (21) 48x-54y=-3186 24x+y=1080 \u7b54\u6848\uff1ax=45 y=99 (22) 36x+77y=7619 47x-y=799 \u7b54\u6848\uff1ax=17 y=91 (23) 13x-42y=-2717 31x-y=1333 \u7b54\u6848\uff1ax=43 y=78 (24) 28x+28y=3332 52x-y=4628 \u7b54\u6848\uff1ax=89 y=30 (25) 62x-98y=-2564 46x-y=2024 \u7b54\u6848\uff1ax=44 y=54 (26) 79x-76y=-4388 26x-y=832 \u7b54\u6848\uff1ax=32 y=91 (27) 63x-40y=-821 42x-y=546 \u7b54\u6848\uff1ax=13 y=41 (28) 69x-96y=-1209 42x+y=3822 \u7b54\u6848\uff1ax=91 y=78 (29) 85x+67y=7338 11x+y=308 \u7b54\u6848\uff1ax=28 y=74 (30) 78x+74y=12928 14x+y=1218 \u7b54\u6848\uff1ax=87 y=83 (31) 39x+42y=5331 59x-y=5841 \u7b54\u6848\uff1ax=99 y=35 (32) 29x+18y=1916 58x+y=2320 \u7b54\u6848\uff1ax=40 y=42 (33) 40x+31y=6043 45x-y=3555 \u7b54\u6848\uff1ax=79 y=93 (34) 47x+50y=8598 45x+y=3780 \u7b54\u6848\uff1ax=84 y=93 (35) 45x-30y=-1455 29x-y=725 \u7b54\u6848\uff1ax=25 y=86 (36) 11x-43y=-1361 47x+y=799 \u7b54\u6848\uff1ax=17 y=36 (37) 33x+59y=3254 94x+y=1034 \u7b54\u6848\uff1ax=11 y=49 (38) 89x-74y=-2735 68x+y=1020 \u7b54\u6848\uff1ax=15 y=55 (39) 94x+71y=7517 78x+y=3822 \u7b54\u6848\uff1ax=49 y=41 (40) 28x-62y=-4934 46x+y=552 \u7b54\u6848\uff1ax=12 y=85 (41) 75x+43y=8472 17x-y=1394 \u7b54\u6848\uff1ax=82 y=54 (42) 41x-38y=-1180 29x+y=1450 \u7b54\u6848\uff1ax=50 y=85 (43) 22x-59y=824 63x+y=4725 \u7b54\u6848\uff1ax=75 y=14 (44) 95x-56y=-401 90x+y=1530 \u7b54\u6848\uff1ax=17 y=36 (45) 93x-52y=-852 29x+y=464 \u7b54\u6848\uff1ax=16 y=45 (46) 93x+12y=8823 54x+y=4914 \u7b54\u6848\uff1ax=91 y=30 (47) 21x-63y=84 20x+y=1880 \u7b54\u6848\uff1ax=94 y=30 (48) 48x+93y=9756 38x-y=950 \u7b54\u6848\uff1ax=25 y=92 (49) 99x-67y=4011 75x-y=5475 \u7b54\u6848\uff1ax=73 y=48 (50) 83x+64y=9291 90x-y=3690 \u7b54\u6848\uff1ax=41 y=92 (51) 17x+62y=3216 75x-y=7350 \u7b54\u6848\uff1ax=98 y=25 (52) 77x+67y=2739 14x-y=364 \u7b54\u6848\uff1ax=26 y=11 (53) 20x-68y=-4596 14x-y=924 \u7b54\u6848\uff1ax=66 y=87 (54) 23x+87y=4110 83x-y=5727 \u7b54\u6848\uff1ax=69 y=29 (55) 22x-38y=804 86x+y=6708 \u7b54\u6848\uff1ax=78 y=24 (56) 20x-45y=-3520 56x+y=728 \u7b54\u6848\uff1ax=13 y=84 (57) 46x+37y=7085 61x-y=4636 \u7b54\u6848\uff1ax=76 y=97 (58) 17x+61y=4088 71x+y=5609 \u7b54\u6848\uff1ax=79 y=45 (59) 51x-61y=-1907 89x-y=2314 \u7b54\u6848\uff1ax=26 y=53 (60) 69x-98y=-2404 21x+y=1386 \u7b54\u6848\uff1ax=66 y=71 (61) 15x-41y=754 74x-y=6956 \u7b54\u6848\uff1ax=94 y=16 (62) 78x-55y=656 89x+y=5518 \u7b54\u6848\uff1ax=62 y=76 (63) 29x+21y=1633 31x-y=713 \u7b54\u6848\uff1ax=23 y=46 (64) 58x-28y=2724 35x+y=3080 \u7b54\u6848\uff1ax=88 y=85 (65) 28x-63y=-2254 88x-y=2024 \u7b54\u6848\uff1ax=23 y=46 (66) 43x+50y=7064 85x+y=8330 \u7b54\u6848\uff1ax=98 y=57 (67) 58x-77y=1170 38x-y=2280 \u7b54\u6848\uff1ax=60 y=30 (68) 92x+83y=11586 43x+y=3010 \u7b54\u6848\uff1ax=70 y=62 (69) 99x+82y=6055 52x-y=1716 \u7b54\u6848\uff1ax=33 y=34 (70) 15x+26y=1729 94x+y=8554 \u7b54\u6848\uff1ax=91 y=14 (71) 64x+32y=3552 56x-y=2296 \u7b54\u6848\uff1ax=41 y=29 (72) 94x+66y=10524 84x-y=7812 \u7b54\u6848\uff1ax=93 y=27 (73) 65x-79y=-5815 89x+y=2314 \u7b54\u6848\uff1ax=26 y=95 (74) 96x+54y=6216 63x-y=1953 \u7b54\u6848\uff1ax=31 y=60 (75) 60x-44y=-352 33x-y=1452 \u7b54\u6848\uff1ax=44 y=68 (76) 79x-45y=510 14x-y=840 \u7b54\u6848\uff1ax=60 y=94 (77) 29x-35y=-218 59x-y=4897 \u7b54\u6848\uff1ax=83 y=75 (78) 33x-24y=1905 30x+y=2670 \u7b54\u6848\uff1ax=89 y=43 (79) 61x+94y=11800 93x+y=5952 \u7b54\u6848\uff1ax=64 y=84 (80) 61x+90y=5001 48x+y=2448 \u7b54\u6848\uff1ax=51 y=21 (81) 93x-19y=2 86x-y=1548 \u7b54\u6848\uff1ax=18 y=88 (82) 19x-96y=-5910 30x-y=2340 \u7b54\u6848\uff1ax=78 y=77 (83) 80x+74y=8088 96x-y=8640 \u7b54\u6848\uff1ax=90 y=12 (84) 53x-94y=1946 45x+y=2610 \u7b54\u6848\uff1ax=58 y=12 (85) 93x+12y=9117 28x-y=2492 \u7b54\u6848\uff1ax=89 y=70 (86) 66x-71y=-1673 99x-y=7821 \u7b54\u6848\uff1ax=79 y=97 (87) 43x-52y=-1742 76x+y=1976 \u7b54\u6848\uff1ax=26 y=55 (88) 70x+35y=8295 40x+y=2920 \u7b54\u6848\uff1ax=73 y=91 (89) 43x+82y=4757 11x+y=231 \u7b54\u6848\uff1ax=21 y=47 (90) 12x-19y=236 95x-y=7885 \u7b54\u6848\uff1ax=83 y=40 (91) 51x+99y=8031 71x-y=2911 \u7b54\u6848\uff1ax=41 y=60 (92) 37x+74y=4403 69x-y=6003 \u7b54\u6848\uff1ax=87 y=16 (93) 46x+34y=4820 71x-y=5183 \u7b54\u6848\uff1ax=73 y=43 (94) 47x+98y=5861 55x-y=4565 \u7b54\u6848\uff1ax=83 y=20 (95) 30x-17y=239 28x+y=1064 \u7b54\u6848\uff1ax=38 y=53 (96) 55x-12y=4112 79x-y=7268 \u7b54\u6848\uff1ax=92 y=79 (97) 27x-24y=-450 67x-y=3886 \u7b54\u6848\uff1ax=58 y=84 (98) 97x+23y=8119 14x+y=966 \u7b54\u6848\uff1ax=69 y=62 (99) 84x+53y=11275 70x+y=6790 \u7b54\u6848\uff1ax=97 y=59 (100) 51x-97y=297 19x-y=1520 \u7b54\u6848\uff1ax=80 y=39 1.2x+7y-z=24 \u2460 4x-4y+z=-3 \u2461 x+y=5 \u2462 \u89e3\uff1a\u7531\u2460+\u2461\u5f97\uff1a2x+7y-z+4x-4y+z=24-3 6x+3y=21 \u2463 \u5f97\uff1a6x+3y=21 \u2463 x+y=5 \u2462 \u89e3\uff1a\u7531\u2462\u5f97x=5-y \u2464 \u628a\u2464\u4ee3\u5165\u2463\u4e2d 30-6y+3y=21 -3y=-9 y=3 \u56e0\u6b64\uff1ax=2 y=3 z=1 2.\u4e00\u5143\u4e8c\u6b21\u65b9\u7a0b\u5355\u5143\u590d\u4e60 \u4e00\u3001\u9009\u62e9\u9898\uff1a\uff08\u6bcf\u5c0f\u98982\u5206\uff0c\u517120\u5206\uff09 1\uff0e\u4e0b\u5217\u65b9\u7a0b\u4e2d\u4e0d\u4e00\u5b9a\u662f\u4e00\u5143\u4e8c\u6b21\u65b9\u7a0b\u7684\u662f\uff08 \uff09 A\uff0e\uff08a-3\uff09x2=8\uff08a\u22600\uff09 B\uff0eax2+bx+c=0 C\uff0e\uff08x+3\uff09\uff08x-2\uff09=x+5 D\uff0e 2\uff0e\u5df2\u77e5\u4e00\u5143\u4e8c\u6b21\u65b9\u7a0bax2+c=0\uff08a\u22600\uff09\uff0c\u82e5\u65b9\u7a0b\u6709\u89e3\uff0c\u5219\u5fc5\u987b\u6709C\u7b49\u4e8e\uff08 \uff09 A\uff0e- B\uff0e-1 C\uff0e D\uff0e\u4e0d\u80fd\u786e\u5b9a 3\uff0e\u82e5\u5173\u4e8ex\u7684\u65b9\u7a0bax2+2\uff08a-b\uff09x+\uff08b-a\uff09=0\u6709\u4e24\u4e2a\u76f8\u7b49\u7684\u5b9e\u6570\u6839\uff0c\u5219a\uff1ab\u7b49\u4e8e\uff08 \uff09 A\uff0e-1\u62162 B\uff0e1\u6216 C\uff0e- \u62161 D\uff0e-2\u62161 4\uff0e\u82e5\u5173\u4e8ey\u7684\u4e00\u5143\u4e8c\u6b21\u65b9\u7a0bky2-4y-3=3y+4\u6709\u5b9e\u6839\uff0c\u5219k\u7684\u53d6\u503c\u8303\u56f4\u662f\uff08 \uff09 A\uff0ek>- B\uff0ek\u2265- \u4e14k\u22600 C\uff0ek\u2265- D\uff0ek> \u4e14k\u22600 5\uff0e\u5df2\u77e5\u65b9\u7a0b \u7684\u4e24\u6839\u5206\u522b\u4e3aa\uff0c \uff0c\u5219\u65b9\u7a0b \u7684\u6839\u662f\uff08 \uff09 A\uff0e B\uff0e C\uff0e D\uff0e 6\uff0e\u5173\u4e8ex\u7684\u65b9\u7a0bx2+2\uff08k+2\uff09x+k2=0\u7684\u4e24\u4e2a\u5b9e\u6570\u6839\u4e4b\u548c\u5927\u4e8e-4\uff0c\u5219k\u7684\u53d6\u503c\u8303\u56f4\u662f\uff08 \uff09 A\uff0ek>-1 B\uff0ek<0 C\uff0e-1<k<0 D\uff0e-1\u2264k<0 7\uff0e\u82e5\u65b9\u7a0bx2-kx+6=0\u7684\u4e24\u4e2a\u5b9e\u6570\u6839\u5206\u522b\u6bd4\u65b9\u7a0bx2+kx+6=0\u7684\u4e24\u4e2a\u5b9e\u6570\u6839\u59275\uff0c\u5219k\u7684\u503c\u4e3a\uff08 \uff09 A\uff0e2 B\uff0e C\uff0e5 D\uff0e-5 8\uff0e\u4f7f\u5206\u5f0f \u7684\u503c\u7b49\u4e8e\u96f6\u7684x\u662f\uff08 \uff09 A\uff0e6 B\uff0e-1\u62166 C\uff0e-1 D\uff0e-6 9\uff0e\u65b9\u7a0bx2-4\u2502x\u2502+3=0\u7684\u89e3\u662f\uff08 \uff09 A\uff0ex=\u00b11\u6216x=\u00b13 B\uff0ex=1\u548cx=3 C\uff0ex=-1\u6216x=-3 D\uff0e\u65e0\u5b9e\u6570\u6839 10\uff0e\u5982\u679c\u5173\u4e8ex\u7684\u65b9\u7a0bx2-k2-16=0\u548cx2-3k+12=0\u6709\u76f8\u540c\u7684\u5b9e\u6570\u6839\uff0c\u90a3\u4e48k\u7684\u503c\u662f\uff08 \uff09 A\uff0e-7 B\uff0e-7\u62164 C\uff0e-4 D\uff0e4 \u4e8c\u3001\u586b\u7a7a\u9898\uff1a\uff08\u6bcf\u5c0f\u98983\u5206\uff0c\u517130\u5206\uff09 11\uff0e\u5df2\u77e53- \u662f\u65b9\u7a0bx2+mx+7=0\u7684\u4e00\u4e2a\u6839\uff0c\u5219m=____________\uff0c\u53e6\u4e00\u6839\u4e3a____________\uff0e 12\uff0e\u5df2\u77e5\u65b9\u7a0b3ax2-bx-1=0\u548cax2+2bx-5=0\uff0c\u6709\u5171\u540c\u7684\u6839-1\uff0c\u5219a=____________\uff0cb=____________\uff0e 13\uff0e\u82e5\u4e00\u5143\u4e8c\u6b21\u65b9\u7a0bax2+bx+c=0\uff08a\u22600\uff09\u6709\u4e00\u4e2a\u6839\u4e3a1\uff0c\u5219a+b+c=____________\uff1b\u82e5\u6709\u4e00\u4e2a\u6839\u4e3a-1\uff0c\u5219b \u4e0ea\u3001c\u4e4b\u95f4\u7684\u5173\u7cfb\u4e3a____________\uff1b\u82e5\u6709\u4e00\u4e2a\u6839\u4e3a\u96f6\uff0c\u5219c=____________\uff0e 14\uff0e\u82e5\u65b9\u7a0b2x2-8x+7=0\u7684\u4e24\u6839\u6070\u597d\u662f\u4e00\u4e2a\u76f4\u89d2\u4e09\u89d2\u5f62\u4e24\u6761\u76f4\u89d2\u8fb9\u7684\u957f\uff0c\u5219\u8fd9\u4e2a\u76f4\u89d2\u4e09\u89d2\u5f62\u7684\u659c\u8fb9\u957f\u662f___________\uff0e 15\uff0e\u4e00\u5143\u4e8c\u6b21\u65b9\u7a0bx2-3x-1=0\u4e0ex2-x+3=0\u7684\u6240\u6709\u5b9e\u6570\u6839\u7684\u548c\u7b49\u4e8e________________\uff0e 16\uff0e\u67d0\u98df\u54c1\u8fde\u7eed\u4e24\u6b21\u6da8\u4ef710%\u540e\u4ef7\u683c\u662fa\u5143\uff0c\u90a3\u4e48\u539f\u4ef7\u662f_____________________\uff0e 17\uff0e\u5df2\u77e5\u4e24\u6570\u7684\u79ef\u662f12\uff0c\u8fd9\u4e24\u6570\u7684\u5e73\u65b9\u548c\u662f25\uff0c\u4ee5\u8fd9\u4e24\u6570\u4e3a\u6839\u7684\u4e00\u5143\u4e8c\u6b21\u65b9\u7a0b\u662f___________\uff0e 18\uff0e\u5982\u679c\u5173\u4e8ex\u7684\u65b9\u7a0bx2-2\uff081-k\uff09+k2=0\u6709\u5b9e\u6570\u6839\u03b1\uff0c\u03b2\uff0c\u90a3\u4e48\u03b1+\u03b2\u7684\u53d6\u503c\u8303\u56f4\u662f_______\uff0e 19\uff0e\u8bbeA\u662f\u65b9\u7a0bx2- x-520=0\u7684\u6240\u6709\u6839\u7684\u7edd\u5bf9\u503c\u4e4b\u548c\uff0c\u5219A2=________\uff0e 20\uff0e\u957f\u65b9\u5f62\u94c1\u7247\u56db\u89d2\u5404\u622a\u53bb\u4e00\u4e2a\u8fb9\u957f\u4e3a5cm\u7684\u6b63\u65b9\u5f62\uff0c\u800c\u540e\u6298\u8d77\u6765\u505a\u4e00\u4e2a\u6ca1\u76d6\u7684\u76d2\u5b50\uff0c\u94c1\u7247\u7684\u957f\u662f\u5bbd\u76842\u500d\uff0c\u4f5c\u6210\u7684\u76d2\u5b50\u5bb9\u79ef\u4e3a1\uff0e5 \u7acb\u65b9\u5206\u7c73\uff0c\u5219\u94c1\u7247\u7684\u957f\u7b49\u4e8e________\uff0c\u5bbd\u7b49\u4e8e________\uff0e 1\u3002 4x+y-z=12 3x+2y+z=-5 x-y+5z=12\u3002 2a+7b=3 3a-c=1 -b+3c=43\u3002 x:y=3:2 y:Z=5:4 x+y+z=664\u3002 a-d=-4 d-2y=-1 a+s-d=-15\u3002 a=6s a-4=10s-20d a+12=3y+18d6\u3002 a+s=8 a+d=6 s+d=107\u3002 3(a+s-d)=15(d-a) 5(a+s-d)=400 15+53/6(a+s)=100008\u3002 2a+s+d=15 a+2s+d=16 a+s+2d=179\u3002 2a=3s=6d a+2s+d=1610\u3002 A:S:D=3:4:5 A+S+D=36
1.2x+9y=81
3x+y=34
2.9x+4y=35
8x+3y=30
3.7x+2y=52
7x+4y=62
4.4x+6y=54
9x+2y=87
5.2x+y=7
2x+5y=19
6.x+2y=21
3x+5y=56
7.5x+7y=52
5x+2y=22
8.5x+5y=65
7x+7y=203
9.8x+4y=56
x+4y=21
10.5x+7y=41
5x+8y=44
11.7x+5y=54
3x+4y=38
12.x+8y=15
4x+y=29
8359x+1641y=28359
1641x+8359y=21641
2.在x+3y=3中,若用x表示y,则y=______,用y表示x,则x=______.
4.把方程3(x+5)=5(y-1)+3化成二元一次方程的一般形式为______.
(1)方程y=2x-3的解有______;
(2)方程3x+2y=1的解有______;
(3)方程y=2x-3与3x+2y=1的公共解是______.
9.方程x+y=3有______组解,有______组正整数解,它们是______.
11.已知方程(k2-1)x2+(k+1)x+(k-7)y=k+2.当k=______时,方程为一元一次方程;当k=______时,方程为二元一次方程.
12.对二元一次方程2(5-x)-3(y-2)=10,当x=0时,则y=______;当y=0时,则x=______.
13.方程2x+y=5的正整数解是______.
14.若(4x-3)2+|2y+1|=0,则x+2=______.
的解.
当k为______时,方程组没有解.
______.
(二)选择
24.在方程2(x+y)-3(y-x)=3中,用含x的代数式表示y,则[ ]
A.y=5x-3;
B.y=-x-3;
D.y=-5x-3.
[ ]
26.与已知二元一次方程5x-y=2组成的方程组有无数多个解的方程是[ ]
A.10x+2y=4;
B.4x-y=7;
C.20x-4y=3;
D.15x-3y=6.
[ ]
A.m=9;
B.m=6;
C.m=-6;
D.m=-9.
28.若5x2ym与4xn+m-1y是同类项,则m2-n的值为 [ ]
A.1;
B.-1;
C.-3;
D.以上答案都不对.
29.方程2x+y=9在正整数范围内的解有[ ]
A.1个;
B.2个;
C.3个;
D.4个.
[ ]
A.4;
B.2;
C.-4;
D.以上答案都不对.
二元一次方程组•综合创新练习题
一、综合题
【Z,3,二】
【Z,3,二】
3.已知4ax+yb2与-a3by是同类项求2x-y的值.
【Z,3,二】
4.若|x-2|+(2x-3y+5)2=0,求x和y的值.
【N,3,三】
5.若方程2x2m+3+3y5n-4=7是x,y的二元一次方程组,求m2+n的值.
【Z,3,二】
二、创新题
1.已知x和y互为相反数,且(x+y+4)(x-y)=4,求x和y的值.
【N,4,三】
2.求方程x+2y=7在自然数范围内的解.
【N,4,三】
三、中考题
(山东,95,3分)下列结论正确的是
[ ]
参考答案及点拨
一、1.所考知识点:方程组的解及求代数式的值.
∴ 2m+3n=2×2+3(-3)=4-9=-5.
2.所考知识点:方程的解及解一元一次方程.
解:把 x=-3,y=-2代入方程,得 2(-3)-4(-2)+2a=3解关
点拨:以上两题考察的知识点类似,已知方程的解时,只要把这组数代入方程或方程组就可求出方程中其他字母的值.
3.所考知识点:同类项及解方程
点拨:根据同类项的定义知,相同字母的指数相同,故可列出方程,从而求解.
4.所考知识点:非负数的性质及解简单的二元一次方程组.
点拨:因|x-2|≥0,(2x-3y+5)2≥0,所以,当它们的和为零,这两个数都须是零,即x-2=0,2x-3y+5=0.
5.所考知识点:二元一次方程的定义.
解:由题意知
点拨:从二元一次方程的定义知,未知项的指数为 1,由此得到 2m+3=1, 5n-4=1.
二、1.所考知识点:相反数的意义及解简单的二元一次方程组.
解:由题意,得x+y=0,
又∵(x+y+4)(x-y)=4
∴ 4(x-y)=4
即x-y=1
2.所考知识点:二元一次方程的自然数解.
解:把方程x+2y=7变形,得x=7-2y
令y=1,2,3,4……,则x=5,3,1,-1
1) 66x+17y=3967
25x+y=1200
答案:x=48 y=47
(2) 18x+23y=2303
74x-y=1998
答案:x=27 y=79
(3) 44x+90y=7796
44x+y=3476
答案:x=79 y=48
(4) 76x-66y=4082
30x-y=2940
答案:x=98 y=51
(5) 67x+54y=8546
71x-y=5680
答案:x=80 y=59
(6) 42x-95y=-1410
21x-y=1575
答案:x=75 y=48
(7) 47x-40y=853
34x-y=2006
答案:x=59 y=48
(8) 19x-32y=-1786
75x+y=4950
答案:x=66 y=95
(9) 97x+24y=7202
58x-y=2900
答案:x=50 y=98
(10) 42x+85y=6362
63x-y=1638
答案:x=26 y=62
(11) 85x-92y=-2518
27x-y=486
答案:x=18 y=44
(12) 79x+40y=2419
56x-y=1176
答案:x=21 y=19
(13) 80x-87y=2156
22x-y=880
答案:x=40 y=12
(14) 32x+62y=5134
57x+y=2850
答案:x=50 y=57
(15) 83x-49y=82
59x+y=2183
答案:x=37 y=61
(16) 91x+70y=5845
95x-y=4275
答案:x=45 y=25
(17) 29x+44y=5281
88x-y=3608
答案:x=41 y=93
(18) 25x-95y=-4355
40x-y=2000
答案:x=50 y=59
(19) 54x+68y=3284
78x+y=1404
答案:x=18 y=34
(20) 70x+13y=3520
52x+y=2132
答案:x=41 y=50
(21) 48x-54y=-3186
24x+y=1080
答案:x=45 y=99
(22) 36x+77y=7619
47x-y=799
答案:x=17 y=91
(23) 13x-42y=-2717
31x-y=1333
答案:x=43 y=78
(24) 28x+28y=3332
52x-y=4628
答案:x=89 y=30
(25) 62x-98y=-2564
46x-y=2024
答案:x=44 y=54
(26) 79x-76y=-4388
26x-y=832
答案:x=32 y=91
(27) 63x-40y=-821
42x-y=546
答案:x=13 y=41
(28) 69x-96y=-1209
42x+y=3822
答案:x=91 y=78
(29) 85x+67y=7338
11x+y=308
答案:x=28 y=74
(30) 78x+74y=12928
14x+y=1218
答案:x=87 y=83
(31) 39x+42y=5331
59x-y=5841
答案:x=99 y=35
(32) 29x+18y=1916
58x+y=2320
答案:x=40 y=42
(33) 40x+31y=6043
45x-y=3555
答案:x=79 y=93
(34) 47x+50y=8598
45x+y=3780
答案:x=84 y=93
(35) 45x-30y=-1455
29x-y=725
答案:x=25 y=86
(36) 11x-43y=-1361
47x+y=799
答案:x=17 y=36
(37) 33x+59y=3254
94x+y=1034
答案:x=11 y=49
(38) 89x-74y=-2735
68x+y=1020
答案:x=15 y=55
(39) 94x+71y=7517
78x+y=3822
答案:x=49 y=41
(40) 28x-62y=-4934
46x+y=552
答案:x=12 y=85
(41) 75x+43y=8472
17x-y=1394
答案:x=82 y=54
(42) 41x-38y=-1180
29x+y=1450
答案:x=50 y=85
(43) 22x-59y=824
63x+y=4725
答案:x=75 y=14
(44) 95x-56y=-401
90x+y=1530
答案:x=17 y=36
(45) 93x-52y=-852
29x+y=464
答案:x=16 y=45
(46) 93x+12y=8823
54x+y=4914
答案:x=91 y=30
(47) 21x-63y=84
20x+y=1880
答案:x=94 y=30
(48) 48x+93y=9756
38x-y=950
答案:x=25 y=92
(49) 99x-67y=4011
75x-y=5475
答案:x=73 y=48
(50) 83x+64y=9291
90x-y=3690
答案:x=41 y=92
(51) 17x+62y=3216
75x-y=7350
答案:x=98 y=25
(52) 77x+67y=2739
14x-y=364
答案:x=26 y=11
(53) 20x-68y=-4596
14x-y=924
答案:x=66 y=87
(54) 23x+87y=4110
83x-y=5727
答案:x=69 y=29
(55) 22x-38y=804
86x+y=6708
答案:x=78 y=24
(56) 20x-45y=-3520
56x+y=728
答案:x=13 y=84
(57) 46x+37y=7085
61x-y=4636
答案:x=76 y=97
(58) 17x+61y=4088
71x+y=5609
答案:x=79 y=45
(59) 51x-61y=-1907
89x-y=2314
答案:x=26 y=53
(60) 69x-98y=-2404
21x+y=1386
答案:x=66 y=71
(61) 15x-41y=754
74x-y=6956
答案:x=94 y=16
(62) 78x-55y=656
89x+y=5518
答案:x=62 y=76
(63) 29x+21y=1633
31x-y=713
答案:x=23 y=46
(64) 58x-28y=2724
35x+y=3080
答案:x=88 y=85
(65) 28x-63y=-2254
88x-y=2024
答案:x=23 y=46
(66) 43x+50y=7064
85x+y=8330
答案:x=98 y=57
(67) 58x-77y=1170
38x-y=2280
答案:x=60 y=30
(68) 92x+83y=11586
43x+y=3010
答案:x=70 y=62
(69) 99x+82y=6055
52x-y=1716
答案:x=33 y=34
(70) 15x+26y=1729
94x+y=8554
答案:x=91 y=14
(71) 64x+32y=3552
56x-y=2296
答案:x=41 y=29
(72) 94x+66y=10524
84x-y=7812
答案:x=93 y=27
(73) 65x-79y=-5815
89x+y=2314
答案:x=26 y=95
(74) 96x+54y=6216
63x-y=1953
答案:x=31 y=60
(75) 60x-44y=-352
33x-y=1452
答案:x=44 y=68
(76) 79x-45y=510
14x-y=840
答案:x=60 y=94
(77) 29x-35y=-218
59x-y=4897
答案:x=83 y=75
(78) 33x-24y=1905
30x+y=2670
答案:x=89 y=43
(79) 61x+94y=11800
93x+y=5952
答案:x=64 y=84
(80) 61x+90y=5001
48x+y=2448
答案:x=51 y=21
(81) 93x-19y=2
86x-y=1548
答案:x=18 y=88
(82) 19x-96y=-5910
30x-y=2340
答案:x=78 y=77
(83) 80x+74y=8088
96x-y=8640
答案:x=90 y=12
(84) 53x-94y=1946
45x+y=2610
答案:x=58 y=12
(85) 93x+12y=9117
28x-y=2492
答案:x=89 y=70
(86) 66x-71y=-1673
99x-y=7821
答案:x=79 y=97
(87) 43x-52y=-1742
76x+y=1976
答案:x=26 y=55
(88) 70x+35y=8295
40x+y=2920
答案:x=73 y=91
(89) 43x+82y=4757
11x+y=231
答案:x=21 y=47
(90) 12x-19y=236
95x-y=7885
答案:x=83 y=40
(91) 51x+99y=8031
71x-y=2911
答案:x=41 y=60
(92) 37x+74y=4403
69x-y=6003
答案:x=87 y=16
(93) 46x+34y=4820
71x-y=5183
答案:x=73 y=43
(94) 47x+98y=5861
55x-y=4565
答案:x=83 y=20
(95) 30x-17y=239
28x+y=1064
答案:x=38 y=53
(96) 55x-12y=4112
79x-y=7268
答案:x=92 y=79
(97) 27x-24y=-450
67x-y=3886
答案:x=58 y=84
(98) 97x+23y=8119
14x+y=966
答案:x=69 y=62
(99) 84x+53y=11275
70x+y=6790
答案:x=97 y=59
(100) 51x-97y=297
19x-y=1520
答案:x=80 y=39
1.2x+7y-z=24 ①
4x-4y+z=-3 ②
x+y=5 ③
解:由①+②得:2x+7y-z+4x-4y+z=24-3
6x+3y=21 ④
得:6x+3y=21 ④
x+y=5 ③
解:由③得x=5-y ⑤
把⑤代入④中
30-6y+3y=21
-3y=-9
y=3
因此:x=2
y=3
z=1
2.一元二次方程单元复习
一、选择题:(每小题2分,共20分)
1.下列方程中不一定是一元二次方程的是( )
A.(a-3)x2=8(a≠0) B.ax2+bx+c=0
C.(x+3)(x-2)=x+5 D.
2.已知一元二次方程ax2+c=0(a≠0),若方程有解,则必须有C等于( )
A.- B.-1 C. D.不能确定
3.若关于x的方程ax2+2(a-b)x+(b-a)=0有两个相等的实数根,则a:b等于( )
A.-1或2 B.1或 C.- 或1 D.-2或1
4.若关于y的一元二次方程ky2-4y-3=3y+4有实根,则k的取值范围是( )
A.k>- B.k≥- 且k≠0 C.k≥- D.k> 且k≠0
5.已知方程 的两根分别为a, ,则方程 的根是( )
A. B. C. D.
6.关于x的方程x2+2(k+2)x+k2=0的两个实数根之和大于-4,则k的取值范围是( )
A.k>-1 B.k<0 C.-1<k<0 D.-1≤k<0
7.若方程x2-kx+6=0的两个实数根分别比方程x2+kx+6=0的两个实数根大5,则k的值为( )
A.2 B. C.5 D.-5
8.使分式 的值等于零的x是( )
A.6 B.-1或6 C.-1 D.-6
9.方程x2-4│x│+3=0的解是( )
A.x=±1或x=±3 B.x=1和x=3 C.x=-1或x=-3 D.无实数根
10.如果关于x的方程x2-k2-16=0和x2-3k+12=0有相同的实数根,那么k的值是( )
A.-7 B.-7或4 C.-4 D.4
二、填空题:(每小题3分,共30分)
11.已知3- 是方程x2+mx+7=0的一个根,则m=____________,另一根为____________.
12.已知方程3ax2-bx-1=0和ax2+2bx-5=0,有共同的根-1,则a=____________,b=____________.
13.若一元二次方程ax2+bx+c=0(a≠0)有一个根为1,则a+b+c=____________;若有一个根为-1,则b 与a、c之间的关系为____________;若有一个根为零,则c=____________.
14.若方程2x2-8x+7=0的两根恰好是一个直角三角形两条直角边的长,则这个直角三角形的斜边长是___________.
15.一元二次方程x2-3x-1=0与x2-x+3=0的所有实数根的和等于________________.
16.某食品连续两次涨价10%后价格是a元,那么原价是_____________________.
17.已知两数的积是12,这两数的平方和是25,以这两数为根的一元二次方程是___________.
18.如果关于x的方程x2-2(1-k)+k2=0有实数根α,β,那么α+β的取值范围是_______.
19.设A是方程x2- x-520=0的所有根的绝对值之和,则A2=________.
20.长方形铁片四角各截去一个边长为5cm的正方形,而后折起来做一个没盖的盒子,铁片的长是宽的2倍,作成的盒子容积为1.5 立方分米,则铁片的长等于________,宽等于________.
1。 4x+y-z=12 3x+2y+z=-5 x-y+5z=1
2。 2a+7b=3 3a-c=1 -b+3c=4
3。 x:y=3:2 y:Z=5:4 x+y+z=66
4。 a-d=-4 d-2y=-1 a+s-d=-1
5。 a=6s a-4=10s-20d a+12=3y+18d
6。 a+s=8 a+d=6 s+d=10
7。 3(a+s-d)=15(d-a) 5(a+s-d)=400 15+53/6(a+s)=10000
8。 2a+s+d=15 a+2s+d=16 a+s+2d=17
9。 2a=3s=6d a+2s+d=16
10。 A:S:D=3:4:5 A+S+D=36
4x+3y=5 5x-6y=9
2x-y= -5 7x-4y= -5
x+2y-z=2
x+y+z=6
2x-y-z= -3
1. {x-2y=6
{3x+2y=10
2. {2x+3y=6
{4x-z=10
{z=2 3
3. {2x+3y= -2
{3x-2y=10
4. {3x+y-2z=0
{6x-y+z=1
{9x-y+4z=8
5. {2x+3y=3
{4x-y=13
6. {2x+y+z=2
{x+2y+z=4
{x+y+2z=6
1. x+2y=15 ①
4x+5y=65 ②
解:把②-①*4
解得y=5
把y代入①解得x=10
∴原方程组的解为{X=10
y=5
2. 5x-6y=-3 ①
x+2y=25 ②
解:把②*3+①得
8x=72
x=9
把x=9代入①解得
y=8
∴原方程组的解为{x=9
y=8
3. 3x+2y=23 ①
解:x+y=9 ②
由②得x=9-y ③
把③代入①得
3(9-y)+2y=23
解得y=4
把y=4代入③得
x=5
∴原方程组的解为{x=5
y=4
三元一次
1. x+y+2z=6 ①
2x+3y-5z=-7 ②
x-z=y-4 ③
2. 1/5x-3/5y+6/11z=0.2
x-y+z=1.5
5x-z+15y=74.5
:将x+y+z=50等式两边同时×1500,得1500
x+1500y+1500z=75000
用1500x+2100y+2500z=90000 减去1500
x+1500y+1500z=75000,得600y+1000z=15000,约分,得5z+3y=75 。
接下来开始讨论:
从z=1开始代数,看能除断的为:
z=3;y=20
z=6;y=15
z=9;y=10
z=12;y=5
将这四组数带到x+y+z=50算出x ,共四组解。 (仍是讨论)
x=27,y=20,z=3
x=29,y=15,z=6
x=31,y=10,z=9
x=33,y=5,z=12
帮你搜索到这些,自己写不太可能
4x+3y=5 5x-6y=9
2x-y= -5 7x-4y= -5
x+2y-z=2
x+y+z=6
2x-y-z= -3
1. {x-2y=6
{3x+2y=10
2. {2x+3y=6
{4x-z=10
{z=2 3
3. {2x+3y= -2
{3x-2y=10
4. {3x+y-2z=0
{6x-y+z=1
{9x-y+4z=8
5. {2x+3y=3
{4x-y=13
6. {2x+y+z=2
{x+2y+z=4
{x+y+2z=6
1. x+2y=15 ①
4x+5y=65 ②
解:把②-①*4
解得y=5
把y代入①解得x=10
∴原方程组的解为{X=10
y=5
2. 5x-6y=-3 ①
x+2y=25 ②
解:把②*3+①得
8x=72
x=9
把x=9代入①解得
y=8
∴原方程组的解为{x=9
y=8
3. 3x+2y=23 ①
解:x+y=9 ②
由②得x=9-y ③
把③代入①得
3(9-y)+2y=23
解得y=4
把y=4代入③得
x=5
∴原方程组的解为{x=5
y=4
三元一次
1. x+y+2z=6 ①
2x+3y-5z=-7 ②
x-z=y-4 ③
2. 1/5x-3/5y+6/11z=0.2
x-y+z=1.5
5x-z+15y=74.5
:将x+y+z=50等式两边同时×1500,得1500
x+1500y+1500z=75000
用1500x+2100y+2500z=90000 减去1500
x+1500y+1500z=75000,得600y+1000z=15000,约分,得5z+3y=75 。
接下来开始讨论:
从z=1开始代数,看能除断的为:
z=3;y=20
z=6;y=15
z=9;y=10
z=12;y=5
4x+3y=5 5x-6y=9
2x-y= -5 7x-4y= -5
x+2y-z=2
x+y+z=6
2x-y-z= -3
1. {x-2y=6
{3x+2y=10
2. {2x+3y=6
{4x-z=10
{z=2 3
3. {2x+3y= -2
{3x-2y=10
4. {3x+y-2z=0
{6x-y+z=1
{9x-y+4z=8
5. {2x+3y=3
{4x-y=13
6. {2x+y+z=2
{x+2y+z=4
{x+y+2z=6
1. x+2y=15 ①
4x+5y=65 ②
解:把②-①*4
解得y=5
把y代入①解得x=10
∴原方程组的解为{X=10
y=5
2. 5x-6y=-3 ①
x+2y=25 ②
解:把②*3+①得
8x=72
x=9
把x=9代入①解得
y=8
∴原方程组的解为{x=9
y=8
3. 3x+2y=23 ①
解:x+y=9 ②
由②得x=9-y ③
把③代入①得
3(9-y)+2y=23
解得y=4
把y=4代入③得
x=5
∴原方程组的解为{x=5
y=4
三元一次
1. x+y+2z=6 ①
2x+3y-5z=-7 ②
x-z=y-4 ③
2. 1/5x-3/5y+6/11z=0.2
x-y+z=1.5
5x-z+15y=74.5
:将x+y+z=50等式两边同时×1500,得1500
x+1500y+1500z=75000
用1500x+2100y+2500z=90000 减去1500
x+1500y+1500z=75000,得600y+1000z=15000,约分,得5z+3y=75 。
接下来开始讨论:
从z=1开始代数,看能除断的为:
z=3;y=20
z=6;y=15
z=9;y=10
z=12;y=5
将这四组数带到x+y+z=50算出x ,共四组解。 (仍是讨论)
x=27,y=20,z=3
x=29,y=15,z=6
x=31,y=10,z=9
x=33,y=5,z=12
5x+3y=8,3x+5y=8
6x-7y=5,x+2y=4
10x-8y=14,x+y=5
4x+7y=3,x+y=0
3x+y=10,7x-y=20
44x+10y=27,x+y=1
8x-y=0,x+y=18
11x-y=12,11y-x=-12
5x+6y=27,2x+3y=12
7x-2y=4,x+2y=12
(2x+y)-5y=2,2x-5y=0
7x-3y=3,3x+2y=21
7x+2y=21,y-6x=1
10x-8y=0,3x-2y=2
3x+y=10,5x-7y=8
1.x+y+z=6 (1)
y:z=2:3 (2)
3x-z=0 (3)
由(2)得
y=2/3z (4)
由(3)得
x=1/3z (5)
将(4)、(5)分别带入(1)
1/3z+2/3z+z=6
z=3
y=2/3×3=2
x=1/3×3=1
即x=1,y=2,z=3
2.x/7=y/10=z/5 (1)
2x+3y=44 (2)
由(1)得
x=7y/10
带入(2)
即2×7y/10+3y=44
y=10
x=7×10/10=7
z=y/10×5=10/10×5=5
即x=7,y=10,z=5
绛旓細(鍏朵腑a銆乥銆乧銆乨銆乵銆乶閮芥槸甯告暟)銆涓夊厓涓娆★細aX+bY+cZ=m (1),dX+eY+fZ=n (2),gX+hY+iZ=l (3).鍏堟妸Z褰撳父鏁锛岄偅涔堢敱锛1锛夊拰锛2锛夌粍鎴愮殑鏂圭▼缁勪负浜屽厓涓娆℃柟绋嬬粍锛岀劧鍚庢寜涓婅竟鐨勬柟娉曡В杩欎釜浜屽厓涓娆℃柟绋嬬粍寰梄=[(ae-bd)(m-cZ)-(an-dm+deZ-afZ)]/a(ae-bd),Y=(deZ-afZ+an-...
绛旓細浜屽厓涓娆℃柟绋嬶細1. y=x+3 , 7x+5y=9 2.3s-t=5 锛5s+2t=15 3.3u+2t=7 , 6u-2t=11 4.2a+b=3 , 3a+b=4 涓夊厓涓娆℃柟绋嬶細1.x+y+z=12 x+2y+5z=22 x=4y 2.3x+4z=7 2x+3y+z=9 5x-9y+7z=8 鍙傝冭祫鏂欙細鍒濅竴涓嬪唽鏁板涔 ...
绛旓細1) 66x+17y=3967 25x+y=1200 绛旀锛歺=48 y=47 (2) 18x+23y=2303 74x-y=1998 绛旀锛歺=27 y=79 (3) 44x+90y=7796 44x+y=3476 绛旀锛歺=79 y=48 (4) 76x-66y=4082 30x-y=2940 绛旀锛歺=98 y=51 (5) 67x+54y=8546 71x-y=5680 绛旀锛歺=80 y=59 (6) 42x-95y=...
绛旓細涓鍏冧竴娆℃柟绋嬶細ax+b=0(a,b涓哄疄鏁)浜屽厓涓娆℃柟绋嬶細ax+by+c=0(a,b,c涓哄疄鏁)涓夊厓涓娆℃柟绋嬶細ax+by+cz+d=0(a,b,c,d涓哄疄鏁)
绛旓細鈥滃厓鈥濅唬琛ㄦ湭鐭ユ暟锛屸滄鈥濅唬琛ㄦ湭鐭ユ暟鏈楂樻鏁般備竴鍏冧竴娆℃柟绋嬶細鍚湁1涓湭鐭ユ暟锛屼笖鏈煡鏁版渶楂樻鏁颁负1鐨勬柟绋嬨備緥濡傦細x+3=0 浜屽厓涓娆℃柟绋锛氬惈鏈2涓湭鐭ユ暟锛屼笖鏈煡鏁版渶楂樻鏁颁负1鐨勬柟绋嬨備緥濡傦細x+2y+3=0 涓夊厓涓娆℃柟绋锛氬惈鏈3涓湭鐭ユ暟锛屼笖鏈煡鏁版渶楂樻鏁颁负1鐨勬柟绋嬨備緥濡傦細x+3y+4z+13=0 鍐嶄妇涓...
绛旓細浜屽厓涓娆:f锛坸锛=ax+by+c 浜屽厓涓娆℃柟绋:ax+by+c=0 涓夊厓涓娆℃柟绋 :ax+by+cz+d=0 鍏朵粬鐨勪緷娆$被鎺ㄣ傘傘備綘琛ュ厖鐨剎^2+2+1=(x+1)^2杩欑褰㈠紡鏄湁锛屼絾杩欎笉鏄渶绠褰㈠紡锛屽寲涓烘渶绠褰㈠紡鍚庝负锛歺-1=0锛屼粛鐒舵槸涓鍏冧竴娆℃柟绋嬨傝鏄庯細涓瀹氳鎶婃柟绋嬪寲涓烘渶绠褰㈠紡鍚庢墠鑳藉垽鏂槸浠涔堟柟绋嬶紒鍚﹀垯锛屼緥濡...
绛旓細杩欐椂甯哥敤浠e叆娉曘傛瘮濡傦細x+2z=1 y-z=2 2x+3y+4z=5 鐢扁憼: x=1-2z 鐢扁憽: y=2+z 浠e叆鈶: 2(1-2z)+3(2+z)+4z=5 2-4z+6+3z+4z=5 3z=-3 z=-1 鏁厁=1-2z=3,y=z+2=1
绛旓細瑙o細璁惧钩璺暱Xm锛屽潯璺暱Ym,鍒欐湁锛氳В杩欎釜鏂圭▼缁勫緱x=300(m),y=400(m)鎵浠ユ暣涓矾闀夸负300+400=700锛坢锛
绛旓細鈶ょ敤鈥渰鈥濊仈绔嬩袱涓湭鐭ユ暟鐨勫硷紝灏辨槸鏂圭▼缁勭殑瑙o紱鈶ユ渶鍚庢楠屾眰寰楃殑缁撴灉鏄惁姝g‘锛堜唬鍏ュ師鏂圭▼缁勪腑杩涜妫楠岋紝鏂圭▼鏄惁婊¤冻宸﹁竟=鍙宠竟锛夈涓夊厓涓娆℃柟绋:浠栦滑涓昏鐨勮В娉曞氨鏄姞鍑忔秷鍏冩硶鍜屼唬鍏ユ秷鍏冩硶锛岄氬父閲囩敤鍔犲噺娑堝厓娉曪紝鑻ユ柟绋嬬粍闅捐В灏辩敤浠e叆娑堝厓娉曪紝鍥犻鑰屽紓锛堜笌浜屽厓涓娆℃柟绋鐨勮В娉曠浉浼硷級銆
绛旓細2.x=1 y=10 鎴栬 x=3 y=5 3.瑙o細 x-2y=0 锛1锛 4x+3y=22锛2锛夛紙2锛夊噺锛1锛壝4锛屽緱11y=22锛屾墍浠=2 灏唝=2甯﹀叆锛1锛夛紝寰梮=-4 缁间笂锛屾鏂圭▼缁勭殑瑙d负锛歺=-4锛寉=2 4.瑙o細 3x+2y+5z=2 锛1锛墄-2y-z=6 锛2锛4x+2y-7z=30锛3锛夌敱锛2锛夊緱 x=6+...