把(x+y),(x-y)个作为一个整体合并同类项1,7(x+y)-2(x+y)-4(x+y)+2(x+y)2,(x-y)²_数学解答

把(x+y),(x-y)个作为一个整体合并同类项
1,7(x+y)-2(x+y)-4(x+y)+2(x+y)
2,(x-y)²＋2(x-y)－(x-y)－2(x-y)²

人气：339 ℃　时间：2020-06-26 21:13:13

解答

1,7(x+y)-2(x+y)-4(x+y)+2(x+y)
=3(x+y)
2,(x-y)²＋2(x-y)－(x-y)－2(x-y)²
=-(x-y)²＋(x-y)