Answer:
y = 3x - 6
Explanation:
The slopes of perpendicular lines are negative reciprocals. In other words, if you know one slope, flip it and change the sign to find the other slope.
slope f given line: -1/3
flip it to get -3/1 which is the same as -3.
Change the sign to get 3.
The perpendicular line has slope 3.
y = mx + b
y = 3x + b
Use point (5, 9) for x and y and solve for b.
9 = 3(5) + b
9 = 15 + b
b = -6
y = 3x - 6