=6(x-y)-4(x-y)+4(x+y)-2(x+y)=2(x-y)+2(x+y)=2x-2y+2x+2y=4x
2(X-Y)+2(X+Y)
=2(x-y)+2(x+y)=4x
=6x-6y-2x-2y-4x+4y+4x+4y=(6-2-4+4)x-(6+2-4-4)y=4x
=6x-6y-2x-2y-4x+4y+4x+4y=4x去掉括号展开化简就行了
=6X-6Y-2X-2Y-4X+4Y+4X+4Y=4X答案是4X