已知3x =2y 求x/x+y+y/x-y-y²/x²-y²
已知x/y=2,求2x(x+y)-y(x+y)/4x²-4xy+y²
已知X-Y/X+Y=3,求代数式2(x-y)/X+Y-3X+Y/X+Y
已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)
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+
已知x²+y²+5=2x+4y,求【2x²-(x-y)(x-y)】【(x+y-1)(x-y
已知y-2x=0,求3x²-2y²/(x+y)(x-y)的值
已知x+3y=2,求代数式(x²-y²/x+y)-【2(x+y)】的值
先化简,再求值.已知x=-2,y=125分之一,求x(3x-2y)+(2x+y)²+(2x-y)(x+y)-3
已知x+y=1,xy=-二分之一,求x(x+y)(x-y)-x(x+y)²
已知2x-y=10,求式子[(x^2+y^2)-(x-y)^2+2y(x-y)]/4y (4xy-2y²)/4
已知x²+y²+5=2x+4y,求代数式(2x²-(x+y)(x-y))x((x+y-1)
已知x-3y=0,求(x²-2xy+y²/x-y)-2y的值