Question

Lg(x2+2x+3)=lg3
A) -2,0
B) 2;0
D)-2;2

Answer 1

$lg(x^2+2x+3)=lg3 \\\\ x^2+2x+3\ \textgreater \ 0 \\ x\in(-\infty;+\infty) \\\\ x^2+2x+3=3 \\ x^2+2x=0 \\ x(x+2)=0 \\ x_1=0; x_2=-2$

Ответ: А