Write an equation for a line perpendicular to y = 3 x + 5 and passing through the point (-9,4)

Question

I need help with this math question I tried by myself so many times an I keep on getting the wrong answer I am not sure where I keep on going wrong.

Answer 1

The product of slopes of perpendicular lines is -1, so the slope of the perpendicular line is -1/3.

y = (-1/3)x + b

Use the given point to find b.

4 = (-1/3)(-9) + b

Solve for b and finish from here.