The position of an object moving along a line is given by the function s(t)= - 10t +80t. Find the average velocity of the object

The position of an object moving along a line is given by the function s(t)= - 10t² +80t. Find the average velocity of the object over the following intervals.(a) [1,9] (b) [1, 8](c) [1.7] (d) [1, 1+h] where h> 0 is any real number..(a) The average velocity of the object over the interval [1, 9] is(b) The average velocity of the object over the interval [1, 8] is.