+108 1.) Let \(f\) be defined by
\(f(x) = \left\{ \begin{array}{cl} 3-x & \text{ if } x \leq 3, \\ -x^3+2x^2+3x & \text{ if } x>3. \end{array} \right.\)
Calculate \(f^{-1}(0)+f^{-1}(6).\)
2.) If \(f(x)=\frac{x+4}{x^2+ax+b},\) and \(f(x)\) has two vertical asymptotes at \(x=1\) and \(x=-2\), then find the sum of a and b.
