Please help ! (only right answers please )!

Ineed to know the answer to this algebra question.

What is the point slope form of a line with slope -5 that contains point (2,-1)

In order for the function to be linear, what must m be and why? m = 22 because the rate of change is 1. m = 20 because the rate of change is 3. m = 22 because the rate of change is -1. m = 20 because the rate of change is -3.