如果-x+2y=5,则5(x-2y)²-3（x-2y)-60=

如果-x+2y=5,则5(x-2y)²-3（x-2y)-60= 数学题……555{(3x+y)(3x-y)-(x-5y)(5x-y)-(x-2y)²÷(-4x),x=-2.y |x+2y+3|+(2x+y)²=0求x²-xy+y² |3x-y+5|+(2x-y+3)²=0 求x=?y=? 求代数式3x²y+5x-0.5x²y+3.5x²y-2的值,其中x=1/5,y=7 已知x/3y=y/2x-5y=6x-5y/x,则4x²-5xy+6y²/x²-2xy+3y [(x+2y)²-（x+y)(3x-y)-5y²]÷(2x),其中x,y满足x²+4x+y 已知（x+2）²+|x+y+5|=0,求3x²y+{-2x²y-[-2xy+（x² 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 1.已知x+y=5,xy=2,则x^4 y^3+x^3 y^4 2.因式分解0.25X²-0.01y² 已知2x²+3y²=6x 则x²+y²+2x的最大值