Velicity Finding Maximum!!! And Average Velicity, Am I Don The Right Track??

Finding Maximum!!! and average velicity, am i don the right track?? - velicity

1. For what value of k (8x + K) / (x ^ 2) is maximal with respect to x = 4?

---- For this problem, I have the equation, found that F and f 'a-8x ^ 2-2xK / x ^ 4 and then I started from scratch and taking x = 4,
I k =- 16, but I checked with the table of characters. No change from positive to negative, to ...
What have I done wrong?

2. The position of a particle in the x-axis at time t, t> 0, in Int. The average speed of partivle for 1 \\ \\ \\ \\ \\ \\ \\ \\ u0026lt; u0026lt = t \\ \\ \\ \\ \\ \\ \\ \\, = E is that?

- I am about what the inside of the integral asked, confused.
(1/e-1) ∫ (1-e) s (t) dt or (1/e-1) ∫ (1-e) v (t) dt?
or I have a (t put) in it?