(3x-y)·()=9x²-y²
(x-y)³+9(x-y)-6(x-y)²
已知x,y满足x²+y²-4x+6y+13=0则(3x+y)²-(3x+y)(3x-y)的
先化简再求值:(x-2y)²-(x+2y)(x-2y)-(x-3y)(x-y).其中x²+9y
求函数f(x,y)=x³-y³+3x²+3y²-9x的极值.
已知x,y的值满足方程组x+2y=3,x-y=-2,求x/(x-y)²+x²-y²/(x+
化简后求值 [(x-2y)²+(x-2y)(x-2y)-2x(2x-y)]÷2x 其中x=2 y=3
9(3x-2y)²-(x-y)²,因式分解
已知4x²+y²-4x-6y+10=0求(2/3x(√9x)+(y²√x/y³)
已知4x²+y²-4x-6y+10=0,求[(2/3)x√(9x)+y²√(x/y
已知4x²+y²-4x-6y+10=0,求(2/3√9x+y²√x/y³)-(x
2x²+1/2y²-2x-3y+5=0,求(2x√9x-y²√x/y³)-(√1
(x-3y)²-3x+9y 分解因式