急求一元二次方程计算题30道 解一元二次方程、速度啊啊啊、数学好的来啊、初三题、急求、明天...
\u6c4270\u9053\u89e3\u4e00\u5143\u4e8c\u6b21\u65b9\u7a0b\u7684\u9898\uff0c\u8981\u7b54\u6848\uff0c\u6025\u6c42(1)x^2-9x+8=0 \u7b54\u6848\uff1ax1=8 x2=1
(2)x^2+6x-27=0 \u7b54\u6848\uff1ax1=3 x2=-9
(3)x^2-2x-80=0 \u7b54\u6848\uff1ax1=-8 x2=10
(4)x^2+10x-200=0 \u7b54\u6848\uff1ax1=-20 x2=10
(5)x^2-20x+96=0 \u7b54\u6848\uff1ax1=12 x2=8
(6)x^2+23x+76=0 \u7b54\u6848\uff1ax1=-19 x2=-4
(7)x^2-25x+154=0 \u7b54\u6848\uff1ax1=14 x2=11
(8)x^2-12x-108=0 \u7b54\u6848\uff1ax1=-6 x2=18
(9)x^2+4x-252=0 \u7b54\u6848\uff1ax1=14 x2=-18
(10)x^2-11x-102=0 \u7b54\u6848\uff1ax1=17 x2=-6
(11)x^2+15x-54=0 \u7b54\u6848\uff1ax1=-18 x2=3
(12)x^2+11x+18=0 \u7b54\u6848\uff1ax1=-2 x2=-9
(13)x^2-9x+20=0 \u7b54\u6848\uff1ax1=4 x2=5
(14)x^2+19x+90=0 \u7b54\u6848\uff1ax1=-10 x2=-9
(15)x^2-25x+156=0 \u7b54\u6848\uff1ax1=13 x2=12
(16)x^2-22x+57=0 \u7b54\u6848\uff1ax1=3 x2=19
(17)x^2-5x-176=0 \u7b54\u6848\uff1ax1=16 x2=-11
(18)x^2-26x+133=0 \u7b54\u6848\uff1ax1=7 x2=19
(19)x^2+10x-11=0 \u7b54\u6848\uff1ax1=-11 x2=1
(20)x^2-3x-304=0 \u7b54\u6848\uff1ax1=-16 x2=19
(21)x^2+13x-140=0 \u7b54\u6848\uff1ax1=7 x2=-20
(22)x^2+13x-48=0 \u7b54\u6848\uff1ax1=3 x2=-16
(23)x^2+5x-176=0 \u7b54\u6848\uff1ax1=-16 x2=11
(24)x^2+28x+171=0 \u7b54\u6848\uff1ax1=-9 x2=-19
(25)x^2+14x+45=0 \u7b54\u6848\uff1ax1=-9 x2=-5
(26)x^2-9x-136=0 \u7b54\u6848\uff1ax1=-8 x2=17
(27)x^2-15x-76=0 \u7b54\u6848\uff1ax1=19 x2=-4
(28)x^2+23x+126=0 \u7b54\u6848\uff1ax1=-9 x2=-14
(29)x^2+9x-70=0 \u7b54\u6848\uff1ax1=-14 x2=5
(30)x^2-1x-56=0 \u7b54\u6848\uff1ax1=8 x2=-7
(31)x^2+7x-60=0 \u7b54\u6848\uff1ax1=5 x2=-12
(32)x^2+10x-39=0 \u7b54\u6848\uff1ax1=-13 x2=3
(33)x^2+19x+34=0 \u7b54\u6848\uff1ax1=-17 x2=-2
(34)x^2-6x-160=0 \u7b54\u6848\uff1ax1=16 x2=-10
(35)x^2-6x-55=0 \u7b54\u6848\uff1ax1=11 x2=-5
(36)x^2-7x-144=0 \u7b54\u6848\uff1ax1=-9 x2=16
(37)x^2+20x+51=0 \u7b54\u6848\uff1ax1=-3 x2=-17
(38)x^2-9x+14=0 \u7b54\u6848\uff1ax1=2 x2=7
(39)x^2-29x+208=0 \u7b54\u6848\uff1ax1=16 x2=13
(40)x^2+19x-20=0 \u7b54\u6848\uff1ax1=-20 x2=1
(41)x^2-13x-48=0 \u7b54\u6848\uff1ax1=16 x2=-3
(42)x^2+10x+24=0 \u7b54\u6848\uff1ax1=-6 x2=-4
(43)x^2+28x+180=0 \u7b54\u6848\uff1ax1=-10 x2=-18
(44)x^2-8x-209=0 \u7b54\u6848\uff1ax1=-11 x2=19
(45)x^2+23x+90=0 \u7b54\u6848\uff1ax1=-18 x2=-5
(46)x^2+7x+6=0 \u7b54\u6848\uff1ax1=-6 x2=-1
(47)x^2+16x+28=0 \u7b54\u6848\uff1ax1=-14 x2=-2
(48)x^2+5x-50=0 \u7b54\u6848\uff1ax1=-10 x2=5
(49)x^2+13x-14=0 \u7b54\u6848\uff1ax1=1 x2=-14
(50)x^2-23x+102=0 \u7b54\u6848\uff1ax1=17 x2=6
(51)x^2+5x-176=0 \u7b54\u6848\uff1ax1=-16 x2=11
(52)x^2-8x-20=0 \u7b54\u6848\uff1ax1=-2 x2=10
(53)x^2-16x+39=0 \u7b54\u6848\uff1ax1=3 x2=13
(54)x^2+32x+240=0 \u7b54\u6848\uff1ax1=-20 x2=-12
(55)x^2+34x+288=0 \u7b54\u6848\uff1ax1=-18 x2=-16
(56)x^2+22x+105=0 \u7b54\u6848\uff1ax1=-7 x2=-15
(57)x^2+19x-20=0 \u7b54\u6848\uff1ax1=-20 x2=1
(58)x^2-7x+6=0 \u7b54\u6848\uff1ax1=6 x2=1
(59)x^2+4x-221=0 \u7b54\u6848\uff1ax1=13 x2=-17
(60)x^2+6x-91=0 \u7b54\u6848\uff1ax1=-13 x2=7
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1.\u5728\u957f\u4e3a10\uff08\u6839\u53f75+1\uff09cm\u7684\u7ebf\u6bb5AB\u4e0a\u6709\u4e00\u70b9C, \u4e14\u6709AC^2=AB*BC\uff0c\u5219AC\u957f?
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3.\u5728\u7b49\u8170\u4e09\u89d2\u5f62ABC\u4e2d.BC=6.AB.AC\u7684\u957f\u662f\u5173\u4e8ex\u7684\u65b9\u7a0bx^2-10x+m=0\u7684\u4e24\u4e2a\u6574\u6570\u6839,\u6c42m
4.\u752822\u339d\u957f\u7684\u94c1\u4e1d\u80fd\u4e0d\u80fd\u6298\u6210\u4e00\u4e2a32\u5e73\u65b9\u5398\u7c73\u7684\u77e9\u5f62\uff1f\u8bf4\u660e\u7406\u7531
5.\u82e5a\u4e3a\u6709\u7406\u6570,\u8bd5\u63a2\u6c42\u5f53b\u4e3a\u4f55\u503c\u65f6,\u5173\u4e8ex\u7684\u4e00\u5143\u4e8c\u6b21\u65b9\u7a0bx^2+3(a-1)x+(2a^2+a+b)=0\u7684\u6839\u4e3a\u6709\u7406\u6570?
6.\u8bbe\u5173\u4e8ey\u7684\u4e00\u5143\u4e8c\u6b21\u65b9\u7a0b3(m-2)y^2-2(m+1)y-m=0\u6709\u6b63\u6574\u6570\u6839\uff0c\u8bd5\u63a2\u6c42\u6ee1\u8db3\u6761\u4ef6\u7684\u6574\u6570m
\u4e00,\u9009\u62e9\u9898:
1,\u4e0b\u5217\u65b9\u7a0b(1)-x2+2=0 (2)2x2-3x=0 (3)-3x2=0 (3)-3x2=0 (4)x2+=0 (5)=5x (6)2x2-3=(x-3)(x2+1)\u4e2d\u662f\u4e00\u5143\u4e8c\u6b21\u65b9\u7a0b\u7684\u6709( )
A,2\u4e2a B,3\u4e2a C,4\u4e2a D,5\u4e2a
2,\u4e0b\u5217\u914d\u65b9\u6b63\u786e\u7684\u662f( )
x2+3x=(x+)2- (2)x2+2x+5=(x+1)2+4
(3)x2-x+=(x-)2+ (4)3x2+6x+1=3(x+1)2-2
A,(1)(3) B,(2)(4) C,(1)(4) D,(2)(3)
3,\u65b9\u7a0b(x-1)2+(2x+1)2=9x\u7684\u4e00\u6b21\u9879\u7cfb\u6570\u662f( )
A,2 B,5 C,-7 D,7
4,\u65b9\u7a0bx2-3x+2-m=0\u6709\u5b9e\u6839,\u5219m\u7684\u53d6\u503c\u8303\u56f4\u662f( )
A,m>- B,m\u2265 C,m\u2265- D,m>
5,\u65b9\u7a0b(m+1)x2-(2m+2)x+3m-1=0\u6709\u4e00\u4e2a\u6839\u4e3a0,\u5219m\u7684\u503c\u4e3a( )
A, B, C,- D,-
6,\u65b9\u7a0bx2-mx+=0\u7684\u5927\u6839\u4e0e\u5c0f\u6839\u7684\u5dee\u662f( )
A,0 B,1 C,m D,m+1
7,\u5982\u679c\u5173\u65bcx\u7684\u65b9\u7a0b3ax2-2(a-1)x+a=0\u6709\u5b9e\u6570\u6839,\u5219a\u7684\u53d6\u503c\u8303\u56f4\u662f( )
A,a<\u4e14a\u22600 B,a\u2265 C,a\u2264\u4e14a\u22600 D,a\u2264
8,\u82e5\u65b9\u7a0b2x(kx-4)-x2+6=0\u6ca1\u6709\u5b9e\u6570\u6839,\u5219k\u7684\u6700\u5c0f\u6574\u6570\u503c\u662f( )
A,1 B,2 C,3 D,4
9,\u4e00\u5143\u4e8c\u6b21\u65b9\u7a0b\u4e00\u6839\u6bd4\u53e6\u4e00\u6839\u59278,\u4e14\u4e24\u6839\u4e4b\u548c\u4e3a6,\u90a3\u9ebd\u8fd9\u4e2a\u65b9\u7a0b\u662f( )
A,x2-6x-7=0 B,x2-6x+7=0 C,x2+6x-7=0 D,x2+6x+7=0
10,\u65b9\u7a0b3=2x-6\u53d8\u5f62\u4e3a\u6709\u7406\u65b9\u7a0b\u5e94\u662f( )
A,4x2-33x+54=0 B,4x2-27x+42=0 C,4x2+21x+42=0 D,4x2-33x+38=0
11,\u901a\u8fc7\u6362\u5143,\u628a\u65b9\u7a0b3x2+15x+2=2\u5316\u4e3a\u6574\u5f0f\u65b9\u7a0b,\u4e0b\u9762\u7684\u6362\u5143\u4e2d,\u6b63\u786e\u7684\u662f\u8bbe( )
A,=y B,3x2+15x=y C,=y D,x2+5x+1=y
12,\u53bb\u5206\u6bcd\u89e3\u5173\u65bcx\u7684\u65b9\u7a0b\u4ea7\u751f\u589e\u6839,\u5219m\u7684\u503c\u662f( )
A,2 B,1 C,-1 D,\u4ee5\u4e0a\u7b54\u6848\u90fd\u4e0d\u5bf9
13,\u4e0b\u9762\u56db\u7ec4\u6570\u2460\u2461\u2462\u2463\u4e2d,\u662f\u65b9\u7a0b\u7ec4\u7684\u89e3\u7684\u662f( )
A,\u2460\u548c\u2463 B,\u2461\u548c\u2463 C,\u2460\u548c\u2461 D,\u2462\u548c\u2463
14,\u5df2\u77e5\u65b9\u7a0b\u7ec4,\u6709\u4e24\u4e2a\u76f8\u7b49\u7684\u5b9e\u6570\u89e3,\u5219m\u7684\u503c\u4e3a( )
A,1 B,-1 C, D,\u00b11
\u4e8c,\u586b\u7a7a\u9898:
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\u5728\u5b9e\u6570\u8303\u56f4\u5185\u5206\u89e3\u56e0\u5f0f:2x2-4x-3=____________.
\u65b9\u7a0b8x2-(k-1)x+k-7=0\u7684\u4e00\u4e2a\u6839\u662f0,\u5219k=____________.
\u4ee5-\u548c\u4e3a\u6839\u7684\u4e00\u5143\u4e8c\u6b21\u65b9\u7a0b\u662f____________.
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\u4e09,\u89e3\u65b9\u7a0b.6(x2+)+5(x+)-38=0
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\u5341\u5b57\u4ea4\u53c9\u6cd5
\u539f\u65b9\u7a0b\u53ef\u5316\u4e3a\uff084x+20)*(x+70)=0 \u89e3\u5f97x=-70.x=-50
\u5177\u4f53\u505a\u6cd5\uff1a4x 20
x 70
\u7ad6\u7740\u4e58 4x^2 1400
\u4ea4\u53c9\u76f8\u4e58\u518d\u76f8\u52a0 70*4x+20x=300x
\u770b\u5f97\u51fa\u6211\u600e\u4e48\u505a\u7684\u5417\uff1f\u4f60\u4e5f\u53ef\u4ee5\uff0c\u8bd5\u8bd5\uff1f
1、解方程:x2—2x—1=0.
2、解方程:
3、解方程:x2+x- +1=0.
4、解方程:
5、 用配方法解方程:
6、解方程:3 ( x - 5 )2 = 2 ( 5- x )
7、解方程: .
8、
9、解方程:(x -1)2 + 2x (x - 1) = 0
10、解方程: .
11、用配方法解方程: 。
12、解方程: .
13、解方程:x2-6x+1=0.
14、用配方法解一元二次方程:
15、解方程: .
参考答案
一、计算题
1、解:a=1,b=-2,c=-1
B2-4ac=(-2)2-4*1*(-1)=8
X=
方程的解为x=1+ x=1-
2、原方程化为
∴
即
∴ ,
3、解:设x2+x=y,则原方程变为y- +1=0.
去分母,整理得y2+y-6=0,
解这个方程,得y1=2,y2=-3.
当y=2 时,x2+x=2,整理得x2+x-2=0,
解这个方程,得x1=1,x2=-2.
当y=-3 时,x2+x=-3,整理得x2+x+3=0,
∵△=12-4×1×3=-11<0,所以方程没有实数根.
经检验知原方程的根是x1=1,x2=-2.
4、解:移项,得 配方,得
∴ ∴
(注:此题还可用公式法,分解因式法求解,请参照给分)
5、)解:移项,得x2 +5x=-2,
配方,得
整理,得( )2=
直接开平方,得 =
∴x1= ,x2=
6、解:
7、解:
∴ 或
∴ ,
8、
9、解法一:
∴ ,
解法二:
∵ a = 3,b = 4,c = 1
∴
∴
∴ ,
10、解: - -两边平方化简,
两边平方化简 . --
解之得 ---
检验:将 .
当
所以原方程的解为 -
11、解:两边都除以2,得 。
移项,得 。
配方,得 ,
。
或 。
, 。
12、解:方程两边同乘以 ,得
整理得
或
经检验 , 都是原方程的根.
13、解法1:x2-6x+1=0
∵ b2-4ac=(-6)2-4=32
∴ x=
=
=3±2 .
即x1=3+2 ,x2=3-2 .
解法2:x2-6x+1=0
(x-3)2-8=0
(x-3)2 =8
x-3=±2
即x1=3+2 ,x2=3-2 .
14、 解:移项,得
二次项系数化为1,得
配方
由此可得
,
15、解法一:
或
解法二:
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绛旓細宸茬煡鍏充簬x鐨鏂圭▼x2-2x-2n=0鏈変袱涓笉鐩哥瓑鐨勫疄鏁版牴锛庯紙1锛夋眰n鐨勫彇鍊艰寖鍥达紱锛2锛夎嫢n锛5锛屼笖鏂圭▼鐨勪袱涓疄鏁版牴閮芥槸鏁存暟锛屾眰n鐨勫硷紟鑰冪偣锛氭牴鐨勫垽鍒紡锛庝笓棰橈細璁$畻棰锛庡垎鏋愶細锛1锛夊叧浜巟鐨勬柟绋媥2-2x-2n=0鏈変袱涓笉鐩哥瓑鐨勫疄鏁版牴锛屽嵆鍒ゅ埆寮忊柍=b2-4ac锛0锛庡嵆鍙緱鍒板叧浜巒鐨勪笉绛夊紡锛屼粠鑰屾眰寰梟鐨勮寖鍥...
绛旓細瑙h鍞环搴斿畾涓簒鍏冿紝娑0.5鍏冨皯鍗10浠讹紝娑1鍏灏戝崠20浠 锛坸-8锛塠200-(x-10)*20]=640 (x-8)(400-20x)=640 400x-20x²-3200+160x=640 -20x²+560x-3840=0 x²-28x+192=0 (x-12)鎴(x-14)=0 x1=12鎴杧2=14 娉細杩欑姣忔瘡闂鎵惧嚭閲忥紝鍐嶆壘鍑哄崟浣嶅埄娑︼紝鐩镐箻...
绛旓細鎬ユ眰 涓鍏冧簩娆℃柟绋 鎴戞潵绛 1涓洖绛 #鐑# 濠氬Щ骞朵笉骞哥鐨勭埗姣,涓轰粈涔堜篃浼氬偓濠?榛戠櫧璋僟瀹 2015-07-20 路 TA鑾峰緱瓒呰繃442涓禐 鐭ラ亾灏忔湁寤烘爲绛斾富 鍥炵瓟閲:209 閲囩撼鐜:100% 甯姪鐨勪汉:90.8涓 鎴戜篃鍘荤瓟棰樿闂釜浜洪〉 鍏虫敞 灞曞紑鍏ㄩ儴 鏇村杩介棶杩界瓟 杩界瓟 杩介棶 绌虹潃鐨勯兘瑕 宸茶禐杩 宸茶俯...
绛旓細鐢遍鎰弜1+x2=m-1锛寈1x2=n y1+y2=-n-1,y1y2=-6m 鍥犱负x1-y1=2锛寈2-y2=2 鍒檟1锛媥2-(y1+y2)=4 鍗砿锛1锛媙锛1锛漨锛媙锛4 x1锛漼1锛2锛寈2锛漼2锛2 鍒檟1x2锛漼1y2锛2锛坹1+y2锛+4=-6m-2n-2+4=n 鍒6m+3n=2 鍒檓锛-10/3,n锛22/3 鍙傝冭祫鏂欙細浠呬緵鍙傝冿紝璋㈣阿 ...
绛旓細-2x1x2 =(m-2)²+2(m+3)=m²-4m+4+2m+6 =m²-2m+10 =(m-1)²+9 鎵浠=1鏃舵渶灏忥紝鏈灏忓兼槸9 濡傛灉鏈鏈変粈涔堜笉鏄庣櫧鍙互杩介棶锛屽鏋滄弧鎰忚鐐瑰嚮鍙充笅瑙掆滈噰绾充负婊℃剰鍥炵瓟鈥濆鏋滄湁鍏朵粬闂璇烽噰绾虫湰棰樺悗鍙﹀彂鐐瑰嚮鍚戞垜姹傚姪锛岀瓟棰樹笉鏄擄紝璇疯皡瑙o紝璋㈣阿銆傜瀛︿範杩涙锛
绛旓細娉細鍘熼涓殑鈥滄渶灏忓尖濆簲璇ヤ负鈥滄渶澶у尖1.y=-1/4 x²-2x-3=-1/4锕檟+4锕²+1 2.椤剁偣涓猴紙-4锛1锛夛紝瀵圭О杞翠负鐩寸嚎锛歺=-4锛3.鈭-1/4锛0,鈭村綋x锛-4鏃讹紝y闅弜鐨勫澶ц屽噺灏忥紱褰搙锛-4鏃讹紝y闅弜鐨勫澶ц屽澶э紱4.鈭-1/4锛0,鈭村綋x=-4鏃讹紝y鏈夋渶澶у1锛5.鎶妝=0...
绛旓細鈭2x-y=0鎴3x-y=0,y=2x鎴杫=3x 褰搚=2x鏃讹紝2x=x^2+6x+4,x^2+4x+4=0,(x+2)^2=0,x=-2,y=2x=-4 褰搚=3x鏃讹紝3x=x^2+6x+4,x^2+3x+4=0,鏂圭▼鏃犺В 鈭村師鏂圭▼缁勬湁涓涓В锛歺=-2,y=-4 2.鐩存帴浠e叆 鎶妝=mx+2浠e叆涓嬪紡锛屽緱(mx+2)^2+4x+1=2mx+4 m^2x^2+4mx+4...
绛旓細鍥炵瓟锛2.+_1/6 3.+_9/2