先化简,再求值5x²-[2xy-3(⅓xy 2) 4x²]其中x=﹣2-搜答案-智慧作业帮

先化简,再求值：已知,化简xy(x+y的平方）-y的平方(xy-x)+2x(x-y的平方),并求它们的值.x+y=5,2x-y=1＝＝>x＝2,y＝3xy(x+y^2)-y^2(xy-x)+2x(x-

原式=2xy+x+3x(x−1)÷y(x2+2x−3)(x−1)2=2xy+x+3x(x−1)•(x−1)2y(x−1)(x+3)=3xy，当x=2+3，y=2-3时，原式=1(2+3)(2−3)=1

解原式=5x2-[2xy-xy-6+4x2]=5x2-xy+6-4x2=x2-xy+6

[-(xy)/(x-y)^2]^4*[(x^2-xy)/x]^3*x^4/y^10÷[x/(xy-y^2)]^5=(x^4y^4)/(x-y)^8*(x-y)^3*x^4/y^10*[y^5(x-y)

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

令t=xy方程变为：[(t-2)^2+4t-4]/(-t)=(t^2-4t+4+4t-4)/(-t)=-t=-xy又x=10,y=-1/25-xy=-10*(-1/25)=2/5

原式=-3x³y³+6x^4y^4+4x²y³*2x²y=-3x³y³+6x^4y^4+8x^4y^4=-3x³y&su

|x-2|²+(y-3)²=0x-2=0,y-3=0x=2,y=3原式=3xy-[2x-2xy-(3x+xy)-5y]=3xy-(2x-2xy-3x-xy-5y)=3xy-2x+2

:(1)2x2-5x+x2+4x,其中x=-3=3x²-x=3x(-3)²+3=27+3=30(2)(3x2-xy-2y2)-2(x2+xy-2y2),其中x=6,y=-1=3x&

x^+(5x^-xy)-2(x^-3xy)=x^+5x^-xy-2x^+6xy=(x^+5x^-2x^)-(xy-6xy)=4x^+5xy=4*(-1/2)^+5*(-1/2)*(-1)=1+5/2=

2x^2y+4x^2y-3xy^2-5xy^2=6x^2y-8xy^2=6×1^2×(-1)-8×1×(-1)^2=-6-8=-14

再答：满意请采纳，谢谢了

原式=3x^2+9=21

当x=-4,y=1/2时5xy^2-[3xy^2-(4xy^2-2x^2y)]+2x^2y-xy^2=5xy²-3xy²+4xy²-2x²y+2x²y

{（xy-2）^2+4xy-4}/(-xy)={(xy-2)^2+2(xy-2)+1+2xy-1}/(-xy)={[(xy-2)+1]^2+2xy-1}/(-xy)={(xy-1)^2+2xy-1}/

你好.这个很简单的!（1）【2x（xy-xy）+xy（xy-x）】÷xy=2x（1-y/x）+xy(1/x-1/y)=x-y,当x=2013,y=2012时,x-y=1.（2）【2x（2x+3）-2x

2(xy-5xy的平方)-(3xy的平方-xy)＝2xy-10xy的平方-3xy的平方＋xy＝3xy-13xy的平方当x=-1,y=1时,原式＝-3＋13＝10

化简的结果是xy(x-2y)再问：过程？！再答：过程太麻烦了，电脑没法打。

4（3x²y—1/2xy²）—5（—xy²+3x²y）,=12x^2y-2xy^2+5xy^2-15x^2y=-3x^2y+3xy^2;【其中x=—1y=2】=