Answer:
y = -1/3 x + 7
Step-by-step explanation:
The constant in the end doesn't matter; what matters is the slope. To find a perpendicular slope, all you have to do is take the reciprocal of the slope and multiply it by -1. As mentioned before, the constant in the end doesn't matter, so the answer could also be y = -1/3x + 10, y = -1/3x -1/2, etc...
Hope this helped.