How to write a standard form equation with an undefined slope?

An equation that has an undefined slope is a vertical line. A vertical line is represented by x = a number. You cannot write an equation for a vertical line in slope intercept form (because of the undefined slope) ... but u can write it in standard form.

lets say u have a vertical line going thru (2,3) ... since it is a vertical line, its equation would be x = 2

to write this in standard form, it would be : x + 0y = 2 <==