# What is the equation in slope intercept form when the slope is undefined?

If the slope of a line is undefined, then the line is a vertical line, so it cannot be written in slope-intercept form, but it can be written in the form: $x = a$, where $a$ is a constant.
If the line has an undefined slope and passes through the point $\left(2 , 3\right)$, then the equation of the line is $x = 2$.