Ответ:
\[\left( 4b^{2} + 11b \right)x = b\]

\[x = \frac{1}{4b + 11}\]
\[\frac{1}{4b + 11} > 0,\ \ 1 > 0\]
\[4b + 11 > 0\]
\[b > - 2\frac{3}{4}\]

\[Ответ:b \in ( - 2,75;0) \cup (0;\ + \infty).\]
\[\left( 4b^{2} + 11b \right)x = b\]

\[x = \frac{1}{4b + 11}\]
\[\frac{1}{4b + 11} > 0,\ \ 1 > 0\]
\[4b + 11 > 0\]
\[b > - 2\frac{3}{4}\]

\[Ответ:b \in ( - 2,75;0) \cup (0;\ + \infty).\]