化简,并求值2(x-2y)²-4(x+3y)(x-3y)-2(x-y).(y+x)-5(-x-1)²
化简,并求值2(x-2y)²-4(x+3y)(x-3y)-2(x-y).(y+x)-5(-x-1)²
[(x+2y)²-(x+y)(3x-y)-5y²]÷(2x),其中x,y满足x²+4x+y
化简:1.2x²-y²+(2y²-3x²)-(2y²+x²)
先化简,再求值:(3x-y)²-2x(4x-5y)-(x+2y)²,其中x=2009,y=-2
先化简,再求值:3xy²(-x²y+2x³y²)-4xy(-xy²)·
(3x-2y)²(3x-2y)²(9x²+4y²)²
①先化简,再求值.4(3x²y—1/2xy²)—5(—xy²+3x²y),其中x
|x+2y+3|+(2x+y)²=0求x²-xy+y²
2x-y=2,求[(x²+y²)-(x-y)²+2y(x-y)]÷4y
已知2x-y=10,求[(x²+y²)-(x-y)²+2y(x-y)]/4y
代数式求值 x÷3y=y÷2x-5y=6x-15y÷x 求4x²-5xy+6y²÷x²-2
化简求值,要详细过程[(y-2x)(-2x-y)-4(x-2y)²]÷3y,其中x=1,y=-3