计算(2x-1 y)的平方-搜答案-搜狗做题网

1、=y²/16x的6次方×4x的4次方/y²=1/4x²2、=(2a-b)/(a²-9b²)-5b/(a²-9b²)=(2a-6

(1/4x的平方-xy+y的平方)/(x-2y)=1/4(x-2y)^2/(x-2y)=1/4(x-2y)=x/4-y/2

（x+2y）²×（x-2y）²=[(x+2y)(x-2y)]²=(x²-4y²)²=x⁴-8x²y²+16y

y/(x²-xy)+2/(y-x)-x/(y²-xy)=[y²+2(-xy)+x²]/(x²y-xy²)=(x-y)²/[(x-y

1.=[(3X-5)+(2X+7)]*[(3X-5)-(2X+7)]=(7X+2)*(X-12)=7X的平方－82X－242.=[(x+y)+1]*[(x+y)-1]=[(x+y)-1]的平方

2x(-xy)^2-x^2(x^2y^2-y^2)=(xy)^2(2x-x^2+1)

（x³＋3x²y-9xy²）-1/2（6x²y＋4x²）=x³＋3x²y-9xy²-3x²y-2x²

x^3*y^(-2)*(x^(-1)*y^2)^2=x^3*y^(-2)*x^(-2)*y^4=xy

(x的平方-y的平方）的-2次方（x+y)的二次方＝（x+y）^2/(x^2-y^2)=(x+y)^2/(x+y)(x-y)=(x+y)/(x-y)

第2题我来回答吧：由X+2Y=（2X+1）/3X+2Y=（Y-X）/4得：3X+6Y=2X+14X+8Y=Y-X即：X=1-6Y5X+7Y=0消去X,得：23Y=5所以Y=5/23,X=-7/23

x(x-1)-(x^2-y)=x^2-x-x^2+y=-(x-y)=-3(x-y)=3x的平方＋y的平方-2xy=(x-y)^2=9

【2（x-y）²-8（x-y)²（x+y）+6y（x-y）²】÷2（x-y）²=2（x-y）²÷2(x-y)²-8（x-y)²（x

(-x+2y)^2=(-x)^2+2×（-x)×(2y)+(2y)^2=x^2+4xy+4y^2

(x+3y)^2+(x-3y)^2=2(x^2+9y^2)2(x^2+9y^2)+2(x^4-y^4)=2(x^4+x^2+9y^2-y^4)

[1]y+2分之y的平方-6y+9除以[3-y]=（3-y)²/(y+2)×/(3-y)=(3-y)/(y+2)[2]x的立方分之x的平方y乘以[-y分之1]=x²y/x³

1.(2x-3y)^2-(y+3x)(3x-y)=4x^2-12xy+9y^2-(3x+y)(3x-y)=4x^2-12xy+9y^2-9x^2+y^2=10y^2-5x^2-12xy2.[(x-y)

/>这里给出三项平方公式：(a+b+c)²=(a+b+c)(a+b+c)=a²+ab+ac+ab+b²+bc+ac+bc+c²=a²+b²+

(a+b+c)的平方=（a+b）²+2c(a+b)+c²=a²+2ab+b²+2ac+2bc+c²(2x-y-1)的平方=(2x-y)²-2

*(x-2y+3分之1)的平方=x^2+(2y)^2+(1/3)^2-2x*2y+2x*(1/3)-2y*(1/3)=x^2+4y^2+1/9-4xy+(2/3)x-(2/3)y

x-y分之2x的平方-y-x分之x的平方-4xy+x-y分之2y的平方-x的平方=2x/(x-y)-(x²-4xy)/(y-x)+(2y-x²)/(x-y)=(2x+x²