x（x-2y）=y(2y-x) ,则y分之x是多少

x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 x（x-2y）=y(2y-x) ,则y分之x是多少 化简y(x+y)+(x+y)(x-y)-x^2 （x-y)(x-y)2(y-x) (x+2y-?）(x-2y+?) y'=（y/x）^2+y/x+4微分方程 y+y'-2y=2x 微分方程y - 2y' + y = x 3x+y=2 -y/x+y=123x+y=2 （-y/x）+y=12 求y''+2y'+y=e^-x/x的通解y''+2y'+y=（e^-x）/x 若3x-5y=0,则x+y/x=（）,x-y/y=（）,2x-3y/2x+3y=( ) 若x+y=4,则多项式1/2(x+y)+4(x-y)-3（x-y）-3/2(x+y)-x+y值是（） 已知方程组{(X+Y)-3(X-Y)=7,2(X+Y)+(X-Y）=-7}则(X+Y)(X-Y)= 设f(x+y,x-y)=x^2-y^2,则f(x,y)= 若f(x+y,y/x)=x^2-y^2,则F(X,Y)= 已知f(x+y,y/x)=x^2-y^2,则f(x,y)= (x+y)(x-y)-(x-y)^2如题 (x+y)(x-y)-(x-y)^2 （x+y）/2- x-y/2=6 3(x+y)=4(x-y) 若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于