(3x²y³)²÷(1/3xy²)²-7x²y²
[x(x²y²-xy)-y(x²-x³y)]÷3x²y
【x(x²y²-xy)-y(x²-x³y)】÷3x²y
因式分解:[x(x²y²-xy)-y(x²-x³y)]÷3x²y
急![(3x+y)²-3(3x-y)(x+y)-(x-3y)(x+3y)]÷(2xy)
(3xy)² · (x²+xy-y²)-3xy(3x³y+3x²y
计算3x[xy-2x(1/y-x/3]+3y(x²-y²)
[-xy/(x-y)²]²×(y²-xy/x)³
计算:(-7x²y)(2x²y-3xy³+xy)
先化简,再求值:{xy(x²-3y)+3xy²}(-2xy)+x³y²(2x-y
x²/xy-x/y
计算:(xy-x²)×x-y/xy
已知x+y=5,xy=3,x³+y³=(x+y)(x²-xy+y²),则1/x&