Since the line crosses the y axis at 2, your y-intercept should be 2. Using rise over run you can compare the equations to the graph. If you convert 3x to a fraction, it would be 3/1x. Since the line is going down 3 and the rise of the y = -3x + 2 is -3, that part is correct. The line also moves over 1 unit, so the run is 1, therefore the correct slope would be -3 or -3/1. Now if you combine what you have it should be y = -3x - 2, which is the same equation as B.
