-7x - 8y = 9 . . . . . (1)
-4x + 9y = -22 . . . . . (2)
(1) x -4 => 28x + 32y = -36 . . . (3)
(2) x -7 => 28x - 63y = 154 . . . (4)
(3) - (4) => 95y = -190 => y = -190/95 = -2
substituting for y = 2 in (1), we have
-7x - 8(-2) = 9 => -7x + 16 = 9 => -7x = 9 - 16 = -7 => x = -7/-7 = 1
Therefore, x = 1 and y = -2.
