y = 3x - 3....slope here is 3. A perpendicular line will contain a negative reciprocal slope. All that means is " flip " the slope and change the sign. So the slope we need is -1/3.
y = mx + b
slope(m) = -1/3
(3,1)....x = 1 and y = 3
now we sub
3 = -1/3(1) + b
3 = -1/3 + b
3 + 1/3 = b
9/3 + 1/3 = b
10/3 = b
so ur perpendicular line is : y = -1/3x + 10/3
