先化简,再求值:(x+y)(x-y)+(x-y)² -(6x² y-2xy² )/2y其中
先化简,再求值:(x+y)(x-y)+(x-y)² -(6x² y-2xy² )/2y其中
①先化简,再求值.4(3x²y—1/2xy²)—5(—xy²+3x²y),其中x
先化简,再求值:(x²)/(x²-2xy+y²)÷(x²+2xy+y²)/(x&
先化简,再求值:(3x-y)²-2x(4x-5y)-(x+2y)²,其中x=2009,y=-2
化简再求值[(x²+y²)²-4x²y²]÷(x²-y&su
(x+y)²-2(x²-y²)+(y-x)²
先化简,再求值:3xy²(-x²y+2x³y²)-4xy(-xy²)·
先化简,再求值:3x²(2y-x)-3y(2x²-y),其中,x=1/3.y=-1/3
化简:1.2x²-y²+(2y²-3x²)-(2y²+x²)
先化简 再求值.4x²-8xy+4y²/ 2x²-2y² 其中 x=2 y=3
已知2x²-3y²=xy,(xy≠0),求值(4xy-x²)/(xy+2y²)的
先化简,再求值∶(1/x-y-1/x+y)÷2y/x²+2xy+y²,其中x=根号下3加根号下2,y