shannon took out a $300,000, 15 year mortgage with an APR of 7% The first month she made an extra payment of $400. What was her ending balance at the end of thst first month?

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.