Mrs. Jackson gives the table below to her students. In order for the function to be linear, what must a be and why? a = 22 because the rate of change is 1. a = 20 because the rate of change is 3. a = 22 because the rate of change is –1. a = 20 because the rate of change is –3.Mrs. Jackson gives the table below to her students. In order for the function to be linear, what must a be and why? a = 22 because the rate of change is 1. a = 20 because the rate of change is 3. a = 22 because the rate of change is –1. a = 20 because the rate of change is –3