#### Answer

6

#### 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 $(f-h)(-3)$. We know that $(f-h)(x)=f(x)-h(x)$.
Therefore, $(f-h)(-3)=((-3)^{2}-9)-((-3)-3)=(9-9)-(-3-3)=(0)-(-6)=0+6=6$.