Answer:
2p + q = 1
9p + 3q + 3 = 0
q = 1 - 2p
replace q = 1 - 2p into 9p + 3q + 3 = 0
9p + 3(1 - 2p) + 3 = 0
9p + 3 - 6p + 3 = 0
3p + 6 =0
3p = -6
p = -2
q = 1 - 2p
q = 1 -2(-2)
q = 1 + 4
q = 5
(-2 , 5)
there for the answer would be
{(-2, 5)}
Hopefully this was helpful <3 :3