QuestionFind the value of $c$ for which the function $f$ is continuous for all $b$ in $(-\infty, \infty)$, defined as: $$f(b) = \begin{cases} c b + 6 & \text{if } b \leq 9 \\ c(b)^2 - 6 & \text{if } b > 9 \end{cases}$$