Functions, Relations & Transformations · Challenge problem

A function $f$ has domain $[-3, 6]$ and range $[-4, 2]$. Let $g(x) = -2f(3x - 6) + 1$. The domain of $g$ is $[p, q]$ and the range of $g$ is $[r, s]$. Find $p + q + r + s$.