化简在求值 x²+x³-6y²+1-5x³-x+(y-x²)+6(x&
x³y³-x²y²-xy+1
化简并求值:4x ³(-y ³)² -3x 乘(-x)²(-y²)&s
化简再求值 4x³(-y³)²-3x×(-x)²(-y²)³
(x+y)²-(x³+y³)÷(x+y)
已知:x+y+z=1,x²+y²+z²=2,x³+y³+z³
1、证明x³+y³≥x²y+y²x
试说明代数式 x³y³ - 1/2x²y + y² - 2x³y&su
先化简,再求值:3xy²(-x²y+2x³y²)-4xy(-xy²)·
已知x+y+z=3,x²+y²+z²=19,x³+y³+z³
3x³-【x³+(6x²-7x)-2(x³-3xy-4y)】,其中x=-1,y=
已知x,y满足x²+y²-4x-6y+13=0,求(-y/x³)³÷(-1/xy
16x³-24x²y²+12xy^4-2y^6