y=|x-2|-|x-8|

【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2= （x+2y)(x-2y)-(2y-x)(-2x-y)其中x=8,y=-8 [(x+2y)(x-2y)-(x-2y)^2+8y(x+y)]除以4x= 9y=3x-(x-1),4(x+y)-(2x+4)=8y 已知x+y/x=11/8,求x-y/x+2y的值 y=2x+8/x求导 y=|x-2|-|x-8| [x(x-y)-y(x-y)+(x+y)(x-y)]÷2x其中x=2012 y=2013 已知x+y/y=11/8,求x-y/x+2y的值. 3x-2y=9 x-3y=2 x+y=5 x+2y=3 y=x 2x+y=8 已知实数x.y满足根号(x+y-8)+根号(8-x-y)=根号(3x-y-4)+根号(x-2y+7),求x,y 已知：3x=8y.求（1）x+y/y (2)2x+3y/x-2y