化简求值:(x+1)²-(x-1)(x²+x+1),其中x=根号2

问题描述:

化简求值:(x+1)²-(x-1)(x²+x+1),其中x=根号2

原式=(x+1)平方-(x-1)(x+1)平方
= (x+1)平方x(1-x+1)
把x=根号2带入
= (根号2+1)平方x (2-根号2)
= (3+2根号2)x(2-根号2)
= 6-3根号2+4根号2-4
=2+根号2
答:式子的解为2+根号2.