(2xy/-mn)²÷8x²/y²乘(-2m/y²)³
计算 (2xy/-mn²)÷8x²/y²×(-2m/y²)³
分解因式 (x+2y)²-x²-2xy -7m(m-n)³+21mn(n-m)²
X²+2xy+y²/xy乘x²-2xy+y²/xy+y²=
计算:(xy-x²)乘 x-y分之xy
x-y/x²÷x²-2xy+y²/xy*(xy-x²)
小明在做化简求值题:(xy-x²)÷xy分之x²-2xy+y²乘x²分之x-y
xy²=2,求代数式xy²乘(-x²y²)乘(1/2xy³)²
已知2x+y=0,求x-2y/x²+xy乘(x²-y²)÷x²-4xy+4y
因式分解:mn(x²+y²)+xy(m²+n²)
1、3m(2x-y)²-3mn²
先化简,再求值:2x²-2y²分之4x²-8xy+4y²乘xy(x-y)分之(x
-2y³+(3xy²-x²y)-2(xy²-y³)