(x^m-1)*(x^n+2)+(x^m+2)*(x^n-1)+(x^m)*(x^n+1)
=(x^m+n+1)+(x^m+n+1)+(x^m+n+1)
=3(x^m+n+1)
=3乘以x的m+n+1次方
-x的m次方+（-x）的m次方
=-(x^m)+(-x)^m
当m为偶数
=-(x^m)+(x^m)
=0
当m为奇数
=-(x^m)-(x^m)
=-2(x^m)
(b-a)^7*(a-b)^n+(a-b)^n+1*(b-a)^6
=-(a-b)^7*(a-b)^n+(a-b)^n+1*(a-b)^6
=-[(a-b)^7+n]+[(a-b)^n+7]
=0