化简求值;(xy-2²)÷ x²-2xy+y²/xy × x²-y²/
先化简,再求值:(x²)/(x²-2xy+y²)÷(x²+2xy+y²)/(x&
1-x²+2xy-y²
先化简,再求值:3xy²(-x²y+2x³y²)-4xy(-xy²)·
x²-4y²/x²+2xy+y²÷x+2y/2x²+2xy
计算:(1).(-2xy²)*(3x²y)²
已知2x²-3y²=xy,(xy≠0),求值(4xy-x²)/(xy+2y²)的
①先化简,再求值.4(3x²y—1/2xy²)—5(—xy²+3x²y),其中x
计算:3(2x²-3xy²)-2(2xy²-3x²y)
3x²-4xy+y²
因式分解 x²-3xy+2y²+x-2
(x+2y)²-x²-2xy
已知x/y=3,求x²+2xy-3y²/x²-2xy+y²