Let $\displaystyle {f{{\left({x}\right)}}}={\left\lbrace\begin{array}{ccc} {7}{x}-{1}&\text{if}&{x}\leq{5}\\-{8}{x}+{b}&\text{if}&{x}>{5}\end{array}\right.}$
If $\displaystyle {f{{\left({x}\right)}}}$ is a function which is continuous everywhere, then we must have
$\displaystyle {b}=$Preview Question 6  
Now for fun, try to graph $\displaystyle {f{{\left({x}\right)}}}$.