I’m not sure what to do for this question usually it would give me the slope but it says “undefined slope” so I don’t know how to solve it

Equaions of lines with undefined slope are written in the next form:
[tex]x=a[/tex]a is the value that takes the vertical line.
If the line passes through (-7,4) that means that it takes a value of -7.
Then, the equation of the line is x = -7