Question

What is the equation of the line perpendicular to `y=13x` that passes through `(7,8)`?

Answer 1

`y = -1/13x + 111`

Explanation:

Since the line is perpendicular to another line with slope `13`, its slope will be `13`'s opposite reciprocal, or `-1/13`. So the line we are trying to find has the equation `y = -1/13x + b`. Since it passes through `(7,8)`, it holds that `8 = -7/13 + b => b = 111`.

So the final equation is `y = -1/13x + 111`