Question

How do you find a standard form equation for the line with (-1, 9) and is perpendicular to the line whose equation is x = 8?

Answer 1

I found `y-9=0`

Explanation:

Your equation `x=8` represents a perfectly VERTICAL line passing through `x=8` so a perpendicular to this one will be any HORIZONTAL line passing through `y=9` (from the condition of having `(-1,9)`).
A horizontal line passing through `(x_0=-1,y_0=9)` has zero slope, `m=0`, and so we can write the general equation:
`y-y_0=m(x-x_0)`
`y-9=0(x+1)`
or
`y-9=0`