3(x-y)-2(x+y)-5(x-y)+4(x+y)+3(x-y)要有过程
问题描述:
3(x-y)-2(x+y)-5(x-y)+4(x+y)+3(x-y)要有过程
答
3(x-y)-2(x+y)-5(x-y)+4(x+y)+3(x-y) = (3- 5 + 3) * (x-y) + (-2+4)(x+y) = (x-y) + 2(x+y) = x -y + 2x +2y = 3x + y