"The solution to the system is (#,#)." I'm really tired and for my life don't know the solution. Help please!

Answer: (4,-5)
Step-by-step explanation:
8y = -40
(divide by 8)
y = -5
(plug it in to one of the equations)
3x + 6*-5 = -18
3x + -30 = -18
3x = 12
x = 4