The slopes of perpendicular lines have a product of -1. The slope of this line is 3 from the graph so the slope of our line will be -1/3. We know the slope of the line and a point (F, G) that belongs to the line so we can use point-slope form.
Point-slope form: y - y₁ = m(x - x₁) and we know that m = -1/3 and (x₁, y₁) = (F, G) so the answer is y - G = -1/3(x - F).
