整数的运算,化简求值

题目

整数的运算,化简求值
先化简,再求值; x(x+1)-(x-1)(x+1),其中x= -1

答案

x(x+1)-(x-1)(x+1)
=(x+1)[x - (x-1)]
=(x+1)
= -1 + 1
=0