Answer
$-\frac{9}{2}$
Work Step by Step
We are given that $f(x)=x^{2}-9$, $g(x)=2x$, and $h(x)=x-3$.
We are asked to find the value of $(g+h)(-\frac{1}{2})$. We know that $(g+h)(x)=g(x)+h(x)$.
Therefore, $(g+h)(-\frac{1}{2})=(2(-\frac{1}{2}))+(-\frac{1}{2}-
\frac{6}{2})=(-\frac{2}{2})+(\frac{-1-6}{2})=(-\frac{2}{2})+(\frac{-7}{2})=-\frac{2}{2}-\frac{7}{2}=\frac{-2-7}{2}=\frac{-9}{2}=-\frac{9}{2}$.