What is the quotient of (x^3+3x^2-4x-12) divided (x^2+5x+6)?

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.