作业帮(x y-2xy)9x y-2)(xy-1)(xy-1)
来源：学生作业帮助网 编辑：作业帮 时间：2024/04/29 08:06:23
x-xy=8(1)xy-y=-9(2)则有(1)-(2):X-XY-XY+Y=X+Y-2XY=8-(-9)=17
1=(x-z-2ab)/xy2=(a²-2ab+b²)/a-b=(a-b)²/a-b=a-
1.2(Xy+Xy)-3(Xy-xy)-4Xy=2*2xy-0-4xy=4xy-4xy=02.1/2ab-5aC-(3acb)+(3aC-4aC)=1/2ab-5ac-3acb-ac=1/2ab-6a
对.前提是x不等于y
25(x²+2xy+y²)-9(x²-2xy+y²)=[5(x+y)]²-[3(x-y)]²=[5(x+y)+3(x-y)][5(x+y)-
2m-6=-2m=2
3xy-[2xy-2(xy-2分之3xy)+xy]+3xy=6xy-[2xy-2xy+3xy+xy)=6xy-4xy=2xy=2×3×3分之1=2
1、已知2x²+xy=10,3y²+2xy=6,求4x²+8xy+9y²的值为?分析：通过观察,可以把8xy拆成2xy+6xy,分别于剩余的两项组合,并提取公因
=xy-3xy+2xy-xy=-xy
∵xy=2，∴x=2y，则原式=(2y)2−2y•y+3y2(2y)2+2y•y+6y2=4y2−2y2+3y24y2+2y2+6y2=512．
把已知两式相加结果为13
xy(y-2)+2(y-2)下步不写了能看懂吧?
(3x^2+2xy)/xy-(2x^2-xy)/xy=(3x^2+2xy-2x^2+xy)/xy=(x^2+3xy)/xy=x(x+3y)/xy=(x+3y)/y
-xy^2+2xy-x=-x(y^2-2y+1)=-x(y-1)^2如果本题有什么不明白可以追问,如果满意请点击“选为满意答案”
3xy-3xy-xy+2yx=-xy+2xy=xy
=(x²y²-4-x²y²-xy+4)/(-2xy)=-xy/(-2xy)=1/2
那9是负的吗～如果不是等于负1,如果是负九等于十七～用第一个等式减第二个等式
原式=-x²y+2xy²+2x²y²-4xy³-3x³+27x³y-18x²y²+2x²y-18x&
x2-2xy+y2-9，=x2-2xy+y2-9，=（x2-2xy+y2）-9，=（x-y）2-32，=（x-y+3）（x-y-3）．