Answer:
x = 7
Explanation:
A line with undefined slope is a vertical line. A vertical line has the equation
x = anumber
The point you were given has an x and a y...(x,y) The first number is the x.
x = 7
That's it, thats the equation of a line with undefined slope that goes through (7, -3).
<<<Fun fact: Lines with 0 slope are horizontal lines and have the equation
y = anumber >>>