Question

【题目】用配方法解方程x2+4x+1=0时，原方程应变形为

A. (x+2)2 = 3 B. (x)2 = 3 C. (x)2 = 5 D. (x)2 = 5

Answer 1

【答案】A

【解析】x2+4x+1=0

x2+4x=-1

x2+4x+4=-1+4

(x+2)2=3

故选A.