To solve this question, we can first look at the part that says the slope of our line is undefined. The slope of a line is undefined if all of the x values are the same, meaning that a line is undefined if it is vertical.
Since we know that this line goes through (3, -2), and we know that it is vertical, we can start to solve. Since vertical lines have all the same x values, the equation of this line is x = 3.