若x²-4x+y²-2y+5=0,则xy+2x²y²+x³y³
x³y³-x²y²-xy+1
先化简,再求值:3xy²(-x²y+2x³y²)-4xy(-xy²)·
已知:x+y+z=1,x²+y²+z²=2,x³+y³+z³
已知x/y=3,求x²+2xy-3y²/x²-xy+y³的值
求函数f(x,y)=2x³+xy²+5x²+y²的极值?
因式分解:m³-2m²-4m+8;x²-2xy+y²-9
16x³-24x²y²+12xy^4-2y^6
(x+y)²-(x³+y³)÷(x+y)
1.已知2x-y=1/3,xy=3,求4x³y-4x²y²+xy³的值(要有计算
试说明代数式 x³y³ - 1/2x²y + y² - 2x³y&su
已知xy²=-2,求-xy(x³y七次方-3x²y五次方-y)
已知4x²+y²-4x-6y+10=0,求(2x/3*√(9x)+y²√(x/y³