The line goes through the points (0, -3) because if you plug x = 0 into x - 2y = 6 and solve for y, you will get  y = -3:

0 - 2y = 6

-2y = 6 multiply both sides by -1

2y = -6 divide both sides by 2

y = -6/2

y = -3

So, one point from the line is (0, -3).

Another point you can get if you plug x = 2 into x - 2y = 6 and solve for y:

2 - 2y = 6

-2y = 6 - 2

- 2y = 4 divide both sides by -2

y = 4/(-2)

y = -2

Second point from the line is (2, -2)