初二下册数学：计算题。先谢了。
\u521d\u4e8c\u4e0b\u518c\u6570\u5b66\uff1a\u8ba1\u7b97\u9898\u3002\u5148\u8c22\u4e86\u3002\u3002\uff0c\u3002\uff0c0.00001=1*10^-5
0.00002=2*10^-5
0.000000567=5.67*10^-7
0.000000301=3.01*10^--7
\u4f60\u597d \u5f88\u9ad8\u5174\u4e3a\u4f60\u89e3\u7b54
1\u3002 =\uff08x+y\uff09\u5206\u4e4b\uff08x+2y\uff09 \u3002 xy \u5206\u4e4b x + 2y \u3002\uff08x+y\u5206\u4e4bxy\uff09
=xy\u5206\u4e4b\uff08x+y\uff09
2. =\uff08 a \u5206\u4e4b 1 + b \u5206\u4e4b 1\uff09² \u3002 \uff08a\u5206\u4e4b1+b\u5206\u4e4b1\uff09\uff08a\u5206\u4e4b1-b\u5206\u4e4b1\uff09
=\uff08 a \u5206\u4e4b 1 + b \u5206\u4e4b 1\uff09\uff08a\u5206\u4e4b1-b\u5206\u4e4b1\uff09
=ab\u5206\u4e4ba-b \u9664\u4ee5 ab\u5206\u4e4ba+b
= \uff08a-b\uff09\u5206\u4e4b\uff08a+b \uff09
\u8bf7\u5927\u5bb6\u4e0d\u8981\u6284\u88ad \u6211\u8f9b\u82e6\u6253\u51fa\u6765\u7684 \u6211\u68c0\u9a8c\u8fc7 \u7edd\u5bf9\u662f\u5bf9\u7684
\u5e0c\u671b\u4f60\u80fd\u91c7\u7eb3
\u6765\u81ea\u6570\u5b66\u91d1\u76d8\u56e2\u961f\u526f\u56e2\u957f
=（x+2y）（x-2y）/(x+2)² × （x+2）/3x（x+2y）
=（x-2y）/(x+2) × 1/3x
=（x-2y）/(3x²+6x)
（4）（y²-x²）/(5x²-4xy) ÷ （x+y）/（5x-4y）
=（y+x）(y-x) / x(5x-4y) × （5x-4y）/（x+y）
=(y-x)/x
和反反复复反反复复反反复复反反复复吩咐
2题答案3x（x+2）分之x-2y
（2）=（x+2y)(x-2y)/(x+2)(x+2)乘（x+2)/3x(x=2y)=x-2y/3x平方+6x
(4)=y-x/x
绛旓細1.鍘熷紡锛4a^2b/3cd^2*5c^2d/4ab^2*3d/2abc =5/2b^2 2.鍘熷紡=-(a+9)(a-9)/(a+3)^2*2(a+3)/(a-9)*(a+3)/(a+9)=-2
绛旓細=(2a²+ab+2b²)/(3a²-3b²)
绛旓細锛2锛夛紙x²-4y²锛/(x²+4x+4) 脳 锛坸+2锛/(3x²+6xy)=锛坸+2y锛夛紙x-2y锛/(x+2)² 脳 锛坸+2锛/3x锛坸+2y锛=锛坸-2y锛/(x+2) 脳 1/3x =锛坸-2y锛/(3x²+6x)锛4锛夛紙y²-x²锛/(5x²-4xy) 梅 锛坸+y锛...
绛旓細鍥炵瓟锛(1)5/4ab (2) 0 (3)x=4
绛旓細鍥犲紡鍒嗚В锛1.鎻愬彇鍏洜寮 12x骞虫柟-12x骞虫柟y-3x骞虫柟y骞虫柟 2.骞虫柟宸叕寮 3ax鍥涙鏂-3ay鍥涙鏂 3.瀹屽叏骞虫柟鍏紡 25m骞虫柟+64-80m 4.鍒嗙粍鍒嗚В 3xy-2x-12y+8 5.鍗佸瓧鐩镐箻娉 x鍥涙鏂-7x骞虫柟y骞虫柟+6y鍥涙鏂 鍒嗗紡锛氬姞鍑 5x/锛坸+y锛+y/(x+y)涔橀櫎 b/锛坅骞虫柟-9锛*锛坅+3锛/锛坆骞虫柟-b锛夋贩鍚...
绛旓細(2) 鑻ユ寜鎵瑰彂浠疯喘涔6鏋濅笌鎸夐浂鍞环璐拱5鏋濈殑娆剧浉鍚,閭ｄ箞杩欎釜瀛︽牎鍏勾绾瀛︾敓鏈夊灏戜汉? 32銆佹煇椤圭揣鎬ュ伐绋,鐢变簬涔欐病鏈夊埌杈,鍙ソ鐢辩敳鍏堝紑宸,6灏忔椂鍚庡畬鎴愪竴鍗,涔欏埌鏉ュ悗淇╀汉鍚屾椂杩涜,1灏忔椂瀹屾垚浜嗗悗涓鍗,濡傛灉璁句箼鍗曠嫭x灏忔椂鍙互瀹屾垚鍚庝竴鍗婁换鍔,閭ｄ箞x搴旀弧瓒崇殑鏂圭▼鏄粈涔? 33銆佽蛋瀹屽叏闀3000绫崇殑閬撹矾,濡傛灉閫熷害澧炲姞25%,...
绛旓細9x^2(x-1)^2-3(x^2-x)-56 =9x^2(x-1)^2-3x(x-1)-56 =[3x(x-1)-8][3x(x-1)+7] =(3x^2-3x-8)(3x^2-3x+7) 鏈夌悊鏁扮粌涔 缁冧範涓(B绾) (涓)璁＄畻棰: (1)23+(-73) (2)(-84)+(-49) (3)7+(-2.04) (4)4.23+(-7.57) (5)(-7/3)+(-7/6) (6)9/4+(-3/2) ...
绛旓細C D 60掳 AA D B C O 渚2 宸茬煡绛夎叞姊舰鐨勫瑙掔嚎浜掔浉鍨傜洿锛岄珮涓5cm锛屾眰姊舰鐨勯潰绉備緥3濡傚浘锛岀瓑鑵版褰BCD涓紝BC=2AD锛孉D鈭C锛孉D=AB锛屾眰鈭燘銆佲垹A鐨勫害鏁般侫 B C D C M B A D 渚4 濡傚浘锛屽湪鐩磋姊舰ABCD涓紝鈭燘=鈭燙=90掳锛孉B=BC锛孧涓築C杈逛笂鐨勪竴鐐癸紝涓斺垹DMC=45掳...
绛旓細2X/(2X-5) - 2/(2X+5)=1 涓よ竟涔樹互(2x-5)(2x+5)2x(2x+5)-2(2x-5)=(2x-5)(2x+5)4x^2+10x-4x+10=4x^2-25 6x=-35 x=-35/6 缁忔楠岋紝x=-35/6鏄師鏂圭▼鐨勮В
绛旓細=33/x(x+22),0,3/x(x+2)+3/(x+2)(x+4)+3/(x+4)(x+6)+...+3/(x+20)(x+22) =3/2[1/x-1/(x+2)+1/(x+2)-1/(x+4)+1/(x+4)-1/(x+6)+...+1/(x+20)-1/(x+22)]=3/2[1/x-1/(x+22)]=33/x(x+22),0,涓閬鍒濅簩鏁板璁＄畻棰 3/x(x+2)+3/...
