the answer is: y = 3x-1
you use the equation y=mx + b. b is your y intercept. in this question, -1 is your y intercept, because the graph passes the y axis at the point (0, -1).
m is also the slope, which is rise over run. so you go up 3 units and 1 unit to the right, which is 3/1 as your m .
overall, your equation of the line is:
y = 3x - 1
