Well, first you want to try and figure out exactly how much is your y increasing by. On the table in your image your y is increasing by 30. What I would do is keep increasing your x's by one and then your y's by 30 till you reach what y equals if x is 12.
x y 4 120 5 150 6 180 7 210 8 240 9 270 10 300 11 330 12 360
