Answer :
x = 1 + y......so sub 1 + y in for x in the other equation
3x - 6y = -12
3(1 + y) - 6y = -12
3 + 3y - 6y = -12
3y - 6y = -12 - 3
-3y = -15
y = -15/-3
y = 5
x = 1 + y
x = 1 + 5
x = 6
solution is (6,5)
3x - 6y = -12
3(1 + y) - 6y = -12
3 + 3y - 6y = -12
3y - 6y = -12 - 3
-3y = -15
y = -15/-3
y = 5
x = 1 + y
x = 1 + 5
x = 6
solution is (6,5)