Answer:
x = -4
Explanation:
You kind of didn't capture the directions in your image, but it looks like maybe they want you to write the equation of the line.
So this is what you need to know: the equation of a vertical (up and down) line is
x = anumber
For future reference on the next question, the equation of a horizontal (flat, left and right) line is
y = anumber
For this question, though, it's vertical.
so x = -4
You can check by picking as many points as you like and find that they ALL have -4 as the x value. Also, you will find the slope formula gives you an answer that is undefined. That's why you can't write an equation using y=mx+b. Hope this helps! I can edit if the question is something wildly different for real.