(1)7(x+y)-2(x+y)-4(x+y)+2(x+y)
(2)(x-y)的平方+2(x-y)-(x-y)-2(x-y)的平方
过程一定要详细!有分的,快点!
(1)7(x+y)-2(x+y)-4(x+y)+2(x+y)
(2)(x-y)的平方+2(x-y)-(x-y)-2(x-y)的平方
过程一定要详细!有分的,快点!
1 7(x+y)-2(x+y)-4(x+y)+2(x+y)=(7-2-4+2)(x-y)=3(x-y)
2 (x-y)的平方+2(x-y)-(x-y)-2(x-y)的平方=(x-y)-(x-y)²