Replace X and Y in the equation with the possible answers. If the equation works then that is the correct answer:
Equation: x - 3y = 8
A) (2,4)
2-3(4) = 2-12 = -10, this does not equal 8 so is not correct.
B) (-1,-3)
-1 - 3(-3) = -1 + 9 = 8, This works correctly, therefore is the correct answer.