Question

If f(x)=x^2+3x, what is the average rate of change of f(x) over the interval [-2,3]?

Answer 1

the average rate of change in the closed interval [ a , b ] is

( f(b) - f(a)))/(b - a)

f(b) = f(3) = 3² + 3(3) = 9 + 9 = 18

f(a) = f(-2) =(-2)² + 3(-2) = 4 - 6 = - 2

= (18 - (-2))/(3 - (-2)) =20/5 = 4