Question

What is an equation of the line that goes through point (8, −9) and whose slope is undefined?

Answer 1

`x=8`

Explanation:

The slope of a line is known as `(rise)/(run)`. When a slope is undefined, the denominator of it is `0`. For example:

`1/0 or 6/0 or 25/0`

This means that there is rise (`y`), but no run (`x`).

For the line to cross the point (`8,-9`), the line would be `x=8`. This way, `x=8` will be a vertical line where all its x-values will always be at `8`. They will never move to the left or right. On the other hand, its y-values will increase up or down. The line would reach `-9` in (`8,-9`).

When a slope is undefined, you do not need to write it, so the equation for the line is `x=8`.