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

Hint: In this problem, we are to find the equation in slope intercept form when the slope is not defined. As the slope is not well defined, the slope intercept form $y = mx + c$ can not be formed. Thus, the slope will be infinite and we can use this information in our solution.

Complete step by step solution:
According to the question, we are trying to find the equation where the slope is undefined.
Now, 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.
The slope-intercept form of a line is given as, y = mx + c, where m is the given slope and c is said to be the y-intercept of the line.
So, if our slope is undefined, then we get, it can not be written as a slope-intercept form.
For example, If the line has an undefined slope and passes through the point (2,3), then the equation of the line is x=2.

Note: The slope intercept form is probably the most frequently used way to express the equation of a line. To be able to use slope intercept form, all that you need to be able to do is 1) find the slope of a line and 2) find the y-intercept of a line.