For what value of the constant $\displaystyle {c}$ is the function $\displaystyle {f}$ continuous on $\displaystyle {\left(-\infty,\infty\right)}$ where
$\displaystyle {f{{\left({s}\right)}}}={\left\lbrace\begin{array}{ccc} {\left({s}\right)}^{{2}}-{c}&\text{if}&{s}\lt{6}\\{c}{\left({s}\right)}+{7}&\text{if}&{s}\geq{6}\end{array}\right.}$


$\displaystyle {c}=$ Preview Question 6