Having trouble with college algebra homework! equations of lines..?

Question

Find an equation of the line having the given slope and containing the given point.

m= -4, (7,9)

The answer is in the form of y=mx+b.

I don't understand how to figure out these types of questions so if you could explain how you get the answer i would appreciate it thanks!

Answer 1

y=mx+b

m=-4

x=7

y=9

9=-4(7)+B

9=-28+B

+28 +28

37=B