\[x^{2} + 4x + 4 = 36\]
\[(x + 2)^{2} = 6^{2}\]
\[x + 2 = 6\]
\[x = 6 - 2\]
\[x = 4;\]
\[x + 2 = - 6\]
\[x = - 6 - 2\]
\[x = - 8.\]
\[Ответ:\ - 8;4.\]