\[\boxed{\text{733.}\text{\ }\text{еуроки}\text{-}\text{ответы}\text{\ }\text{на}\text{\ }\text{пятёрку}}\]
\[bx + 2x = 3b + 6\]
\[x(b + 2) = 3(b + 2)\]
\[1.\ b = - 2\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \]
\[2.\ b \neq - 2\]
\[x( - 2 + 2) = 3( - 2 + 2)\text{\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ }\]
\[\ x(b + 2) = 3(b + 2)\ \ \ \ |\ :(b + 2)\ \]
\[x \cdot 0 = 3 \cdot 0\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \]
\[\ \ x = 3\]
\[0 = 0\]
\[x - любое\ число\]
\[Ответ:x = 3\text{.\ }\]