Answer
$x = 5$
$y = -3$
Work Step by Step
Equations:
$x + 2y = -1$
$x - y = 8$
Making the equations an equivalent system by multiplying the second equation by 2:
$x + 2y = -1$
$2(x - y) = 2(8)$
$x + 2y = -1$
$2x - 2y = 16$
Eliminating $y$ to solve for $x$
$x + 2y = -1$
$+$
$2x - 2y = 16$
$3x = 15$
$x = 5$
Substituting $x$ into the second equation to solve for $y$
$x - y = 8$
$5 - y = 8$
$-y = 3$
$y = -3$