(7x²-4xy+2y²)-2(x²-二分之三y²)
化简:(7x²-4xy+2y²)-2(x²-二分之三y²)并求出x=1y=-1时
求3x²y-2xy²+2(xy-二分之三x²y)-xy+3xy²的值,其中x=3
已知x-y=2,求二分之x²+y²-xy的值
已知x(x-1)-(x²-y)=-2,求二分之x²+y²-xy的值
化简求值:(负三分之一 xy)²[xy(2x-y)-2x(xy-y²)],其中x=-一又二分之一,y
x-y/x²÷x²-2xy+y²/xy*(xy-x²)
先化简,再求值:4x²y-【6xy-2(4xy-2)-xy²】+1.其中x=-二分之一,y=2.
3x²y+xy²-[2xy²-4x²y+(x²y-2xy²)
4x²-2x²-﹙5x²-3x²+二分之三x-y-1﹚其中x=3 y=1先化简再
计算 2xy[4x²y²-3y(xy+x²y)-xy²]
(3x²y-xy²+2xy)/二分之一xy
计算:(-7x²y)(2x²y-3xy³+xy)