the complete question in the attached figure
part A
the x intercept 0 is the point where the ball was hit, the x intercept 20 is the point where the ball fell back to the ground, 20 feet away from the kicker.
the function is increasing in the interval x∈(0, 10) and decreasing in x∈(10, 20)
this means that the height is increasing in the interval (0, 10) and decreasing as x goes through the interval (10,20)
the distance from the kicker is increasing during the whole interval (0, 20)
part B
the rate of change represents the slope of the secant line from A to B. It approximates the rate at which f(x) decreases or increases in the interval
x =[A, B]