through: (5,5), slope = undefined

Answer 1

A line with an undefined slope is a vertical line. Vertical lines have equations of the form $x=a$, where $a$ is a constant.

Since the line passes through the point (5, 5), the equation of the line is:

$$x=5$$

This means that for all points on this line, the x-coordinate will always be 5, while the y-coordinate can take any value.