Each month, a shopkeeper spends 5M + 11 dollars on rent and electricity. If he spends 2M - 3 dollars on rent, how much does he spend on electricity? (subtract the expressions, use keep keep change) *

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.