y-x[1/4-2(y-1/2)]=2(y-1/2)+3

{3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1 x+y+2(-x-y+1)=3(1-y-x)-4-(y+x-1),x+y=? 化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1 先化简 再求值 (2x-y)(y+x)-(x-2y)(2y+x)-(-3y+x)^2其(√x+1)+y^2+4=-4y 已知:【(x²+y²)-(x-y)²+2y(x-y)】/4y=1,求4x/4x²-y²-1/2x+y 已知x-y=1,求[(x+2y)^2+(2x+y)(x-4y)-3(x+y)(x-y)]除以y的值大神们帮帮忙 已知x-y=1,求[(x+2y)²+(2x+y)(x-4y)-3(x+y)(x-y)]÷y的值 [(2x+y)^2+(y+2x)(y-2x)-2y(4x-y)]/4y,其中x=1/2,y=1/3 [(y-2x)(-2x-y)-4(x-2y)²]*2y,其中x=1,y=2 [(y-2x)(-2x-y)+4(x-2y)平方]/3y,其中x=1,y=-3 [(x+y)(x-y)-(x-y)^2-4xy]/2y,其中x=1,y=-1 先化简,再求值：[(x+y)(x-y)-(x-y)^2+2y(x-3y)]/(-4y),其中x=1,y=-2 先化简,再求值:[(x＋y)(x-y)-(x-y)²+2y(x+y)]除4y,其中x=2,y=1 2y(x+二分之一y)-[(x+y)(x-y)+2y(y+x)],其中|x-1|=2 （x-y)(x+y)-(x+y)^2+2y(y-x),其中x=1,y=3. [(-x-y)(-x+y)-(x+y)^2-x(y-y^2)}÷1/2y 化简求值：【(x+Y)(X-Y)-(X-Y)的平方+2Y（2-Y）】除4Y,其中X=1 Y=2 常微分方程的通解dy/dx=(x-y+1)/(x+y-3)y^4=2y^n+y=0y''+6y'+9y=e^(-3x)y''+y'-2y=4e^(2x)