What is the equation of a line that is perpendicular to the line that goes through the points (0, -3) and (-3, 12)?

Question

Can you please give me the steps to solve this. I got m which is -5, but I don't know what to do next.

Answer 1

well, your original line through the points has
m = 15/-3 = -5 as you said
so the perpendicular line has slope
m' = -1/m = -1/-5 = +0.2
It could hit the original line anywhere so we can not find b without a point on the new line.
so
y = 0.2 x + b
is the best we can do.
Is there a part B where you put that through a point?

Answer 2

There were four answers
A: y = 15x + 2
B:y = (-1/15x) - 8
C: y = -9x - 7
D: y = (1/5x) - 3

The answer would be D then, but I still don't understand. Is the perpendicular line's slope always the reciprocal of the original slope?