Answer :
x + 2y = -6.......multiply by -3
3x + 8y = -20
-----------------
-3x - 6y = 18 (result of multiplying by -3)
3x + 8y = -20
----------------add
2y = -2
y = -2/2
y = -1
x + 2y = -6
x + 2(-1) = -6
x - 2 = -6
x = -6 + 2
x = -4
solution is (-4,-1)
3x + 8y = -20
-----------------
-3x - 6y = 18 (result of multiplying by -3)
3x + 8y = -20
----------------add
2y = -2
y = -2/2
y = -1
x + 2y = -6
x + 2(-1) = -6
x - 2 = -6
x = -6 + 2
x = -4
solution is (-4,-1)