Chapter 8 - Coordinate Geometry and Linear Systems - 8.4 - Writing Equations of Lines - Problem Set 8.4 - Page 361: 60

$x-5y =0$

First, we solve for the slope of the perpendicular line: $y =-5x$ Since this is in slope intercept form, we see that the slope is -5. Thus, the slope of the perpendicular line is the opposite reciprocal, which is 1/5. Thus, we use point slope form, and then we simplify to standard form: $y - y_{1} = m(x-x_{1}) \\ y = 1/5(x) \\ 5y = x \\ x -5y =0$