Answer:
x = 1
Explanation:
y = 9 is a horizontal line. It intersects the y axis at (0,9) and for all value s of x, y = 9.
Therefore a line perpendicular to this line will be of the form x = k where k is some constant. It means that for all values of y, the x value is constant. The y value is irrelevant
Since the line passes through (1,-1), ie through x = 1, y = -1, the equation of the line is x = 1