Solve for $x$ in $Ax=b$ USING $A^{-1}.$ Show all steps for full credit.

$A=\left[\begin{array}{ccc}1& 5& -2-9\end{array}\right]$

$b=\left[\begin{array}{c}1\end{array}\right]$

$1$

$A^{-1}=\left[\begin{array}{ccc}-9& -5& 1\end{array}\right]$

$2$