Write the slope intercept form through: (4, -4) and (4, -1)

Your answer is x = 4, or 0 = -x + 4 in the form y = mx + b.
Because both points given have the same x coordinate, the line that passed through them is not sloped, it is just a vertical line. Therefore the equation that represents this line is just x = 4, because this represents a vertical line passing through all points with x coordinate of 4.
I hope this helps!