determine the net change

Question

Determine the net change between x=1 and x=4

f(x)= x²-2x

determine average rate of change

Answer 1

f(1) = 1^2 -2(1) = 1-2 = -1

f(4) = 4^2 - 2(4) = 16-8 = 8

f(4)-f(1) = 8--1 = 9

net change = 9

rate of change = [f(4)-f(1)]/(4-1) = 9/3 = 3