\[\boxed{\text{1136\ (1136).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[(a - 1)^{2} + 4 \cdot (a - 1) - x\]
\[(a - 1)^{2} + 4 \cdot (a - 1) + 4 =\]
\[= \left( (a - 1) + 2 \right)^{2} = (a + 1)^{2}\]
\[x = - 4\]
\[Ответ:\ x = - 4.\ \]