# Question #658c3

Sep 10, 2016

Start inside the expression by finding $g$ "of" -1 or $g \left(- 1\right)$

Substitute $- 1$ for $x$ in $g \left(x\right)$.
$g \left(- 1\right) = {\left(- 1\right)}^{2} - 7 \left(- 1\right) - 9 = - 1$

Now look at the "outside" part of the expression$f$ "of" $g \left(- 1\right)$.

We just found $g \left(- 1\right) = - 1$.
BTW, that's a coincidence that both $x = - 1$ and $g \left(- 1\right) = - 1$.

Substitute $g \left(- 1\right)$ in for $x$ in $f \left(x\right) = x - 2$.

$f \left(g \left(- 1\right)\right) = f \left(- 1\right) = - 1 - 2 = - 3$

I'm not sure why you've listed the numbers -21, -3, 3, and 21, but if you have to find$f \left(g \left(x\right)\right)$ for these values, just follow the same process.