Substitute each value of x, calculate, and if the answer equals to the given value of y, then the point does lie on y = 2x
Point A (1, -1)
y = 2(1)
y = 1
The answer is not y = -1 as given in the question, hence point A does not lie on y = 2x
-----------------------------------------------------------------------------------------------------------
Point B (1, 3)
y = 2(1)
y = 2
The answer is not y = 3 as required, hence point B does not lie on y = 2x
---------------------------------------------------------------------------------------------------------------
Point C(-2, -4)
y = 2(-2)
y = -4
The answer is y = -4 as required. Hence, point C does lie on y = 2x
-----------------------------------------------------------------------------------------------------------------
Point D(-2, 4)
y = 2(-2)
y = -4
The answer is not y = 4 as required, so point D does not lie on y = 2x.
---------------------------------------------------------------------------------------------------------------
Correct Answer: C
