Answer
$y = -3, x = 2$
Work Step by Step
$x + y = -1$
$3x + 2y = 0$
$3(x+y) = -1 \times 3$
$3x + 2y = 0$
$3x + 3y = -3$
$3x + 2y = 0$
$3x - 3x + 3y -2y = -3 - 0$
$y = -3$
$3x + 2 \times -3 = 0$
=>$3x -6 = 0$
=>$3x = 6$
=>$x = 2$