The first step to finding this equation needs to be solving the first equation for y so that we can find the slope.
-3x + y = 1
y = 3x + 1
Now that we have the slope of 3, we know the slope of a perpendicular line would be -1/3. This is because perpendicular lines have opposite and reciprocal slopes. We can then use this and the point to solve in point-slope form.