## Elementary Linear Algebra 7th Edition

$x=-4$ $y=9$
$\begin{pmatrix} x+2 & 8 & -3\\ 1 & 2y & 2x \\ 7 & -2 & y+2 \end{pmatrix}=\begin{pmatrix} 2x+6 & 8 & -3\\ 1 & 18 & -8 \\ 7 & -2 & 11 \end{pmatrix}$ All we need to do here is compare elements: $x+2=2x+6$ $2y=18$ $2x=-8$ $y+2=11$ The first and third equations yield the same result: $x+2=2x+6$ $\quad \quad \quad \quad \quad 2x=-8$ $\implies x=2-6=-4$ $\quad \quad x=\frac{-8}{2}=-4$ The second and fourth equations also yield the same result $2y=18$ $\quad \quad \quad \quad \quad y=11-2=9$ $y=\frac{18}{2}=9$