Ans: (a) All real numbers (b) $-1$
- Consider the first inequality, we have
$\begin{array}{rcl}
x+6 & < & 6(x+11) \\ x+6 & < & 6x + 66 \\ -60 & < & 5x \\ x & > & -12
\end{array}$Therefore, $x>-12$ or $x\le -5$.
Hence, the overall solutions are all real numbers.
- $-1$
