HOMEWORK $9\mathrm{.}1$: Piecewise Functions

Write a UDF that, for a given $x-$value, calculates the value of $f(x)$ where $f(x)$ is the following piecewise function.

$f(x)=\{\begin{array}{cc}-x^2-6x-2\mathrm{.}5,& x0\\ -1\mathrm{.}5-3^{0\mathrm{.}1x},& 0=10\end{array}$

Use this UDF to graph the function from $-5x15.$