This is a twist to the other problems, Crissel. Again, we can use the formula y = mx + b. However, this time they give us a point on the line.
We know the slope is -3. We also know that since the line passes thru point P (2, 0), then when x = 2, y = 0. We can use this info to determine our y-intercept.
If y = mx + b, then
0 = (-3)(2) + b
0 = -6 + b
6 = b = y-intercept
The equation of the line is y = -3x + 6