1. The problem statement, all variables and given/known data I have to find the average velocity of an equation from time 2 to time 4. This equation here is of the position. P = -5*t^3+5*t^2 -4*t. 2. The attempt at a solution Since this is the position i have to take derivative of that. -15t^2-10t-4 Then i substitute 2 for t and i get -44 then i substitute 4 and get -204 ( -44 + -204) / 2 = -124 average velocity. Is this correct? The website where i submit my answers to says it's wrong. Thanks in advance.