Answer:
7
Explanation:
The average rate of change of f(x) in the closed interval [ a, b ] is

here [ a, b ] = [ 4, 6 ]
f(b) = f(6) = 6² - 3(6) - 10 = 36 - 18 - 10 = 8
f(a) = f(4) = 4² - 3(4) - 10 = 16 - 12 - 10 = - 6, hence
average rate of change =
=
= 7