You have to substitute the x points for x & the y points for y: (0,6) (9,15) (6,12) (12,20)
y = 6 + x
6 = 6 + 0
6 = 6
y = 6 + x
15 = 6 + 9
15 = 15
y = 6 + x
12 = 6 + 6
12 = 12
y = 6 + x
20 = 6 + 12
20 = 18
The point that does NOT pass through is (12,20).
