2x+3y-1=y-x-8=x+6 ,y=?

【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2= {3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1 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 2x+3y-1=y-x-8=x+6 ,y=? 已知：3x=8y.求（1）x+y/y (2)2x+3y/x-2y 9y=3x-(x-1),4(x+y)-(2x+4)=8y (3x-y)^2+(3x+y)(3x-y),x=1,y=-2 x+y/2+x-y/3=6,4(x+y)-3(x-y)=-20 {(x+y)/2+(x-y)/3=6 4(x+y)-3(x-y)=-20 4(x+y)-3(x-y)=-20,2/x+y+3/x-y=6 ｛4/(x+y)+6/(x-y)=3 ｛9/(x-y)-1/(x+y)=1 6(x-y)-2(x+y)=14 3(x-y)+(x+y)=5