Answer:
y = (1/3)x
Explanation:
If the y-intercept is (0, 0), then y = mx + b becomes y = mx.
Seeing that y increases by 1, going from (-3, 1) to (0, 0), and that x increases by 3, we determine that the slope, m, is 1/3.
The equation of this line is therefore y = (1/3)x.