已知X2-5X-14=0求(x-1)×(2x-1)-(x+1)2+1
问题描述:
已知X2-5X-14=0求(x-1)×(2x-1)-(x+1)2+1
答
X2-5X-14=0
X2-5X=14
(x-1)×(2x-1)-(x+1)2+1
=2x^2-2x-x+1-x^2-2x-1+1
=x^2-5x+1
=14+1
=15