Answer
$x=-1\pm2\sqrt{3}$
Work Step by Step
Getting the square root of both sides, the solution/s of the given equation, $
(x+1)^2=12
,$ is/are
\begin{array}{l}\require{cancel}
x+1=\pm\sqrt{12}
\\\\
x+1=\pm\sqrt{4\cdot3}
\\\\
x+1=\pm\sqrt{(2)^2\cdot3}
\\\\
x+1=\pm2\sqrt{3}
\\\\
x=-1\pm2\sqrt{3}
.\end{array}
