y=x^2-2x（x

[x(x-y)-y(x-y)+(x+y)(x-y)]÷2x其中x=2012 y=2013 y=(x^2+x)/(x+1) 1、x(x-y)(x+y)-x(x+y)^2 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) y'-2y=(e^x)-x y'+2y/x=x通解 函数,y=3x/(x^2+x+1) ,x 函数y=3x/(x^2+x+1) （x (1)(x^2/x)-y-x-y 先化简再求值(x-y)(x+y)-(x-2y) 的完全平方+x(3x-5y)-(x-y)(x-2y),其中x=1/2 y 【(x-y)^2+(x+y)(x-y)】除以 2x