y = -3x + 5...slope here is -3. A perpendicular line will have a negative reciprocal slope. All thet means is flip the slope and change the sign. So our perpendicular line will have a slope of 1/3....see how I flipped -3, or -3/1, and made it -1/3...and then switched the sign, making it 1/3)
y = mx + b
slope(m) = 1/3
(-3,-5)...x = -3 and y = -5
sub and find b, the y int
-5 = 1/3(-3) + b
-5 = -1 + b
-5 + 1 = b
-4 = b
so ur perpendicular equation is : y = 1/3x - 4