5x²y+y³-3xy²-x³ 按Y的升幂排列是什么?
xy³-8x²y-x³y²-y4次方中,按字母y的降次幂排列为?
x³y³-x²y²-xy+1
已知x/y=3,求x²+2xy-3y²/x²-xy+y³的值
7-2xy-3x²y³+5x³y²z-9x⁴y³z&sup
1已知X-Y=XY=3求(X+Y)²及X³-Y³的值
先化简,再求值:3xy²(-x²y+2x³y²)-4xy(-xy²)·
求函数f(x,y)=2x³+xy²+5x²+y²的极值?
(x+y)²-(x³+y³)÷(x+y)
已知x+y+z=3,x²+y²+z²=19,x³+y³+z³
1.已知2x-y=1/3,xy=3,求4x³y-4x²y²+xy³的值(要有计算
习题15.4 因式分解 5,(3)4xy²-4x²y-y ³ (4)3ax²-3
化简再求值 4x³(-y³)²-3x×(-x)²(-y²)³