The height y (in feet) of a punted football is given by -16/2025x^2 + 9/5x + 2.5 where x is the horizontal distance (in feet) from the point at which the ball is punted.
(a) How high is the ball when it is punted?
(b) What is the maximum height of the punt? (Round your answer to two decimal places.)
(c) How long is the punt? (Round your answer to two decimal places.)

Question

The height y (in feet) of a punted football is given by  -16/2025x^2 + 9/5x + 2.5 where x is the horizontal distance (in feet) from the point at which the ball is punted. 
(a) How high is the ball when it is punted?
(b) What is the maximum height of the punt? (Round your answer to two decimal places.)
(c) How long is the punt? (Round your answer to two decimal places.)

campbell_st · Answer

for (a) let x = 0 and solve

for (b) find the line of symmetry of the curve
         
 for a parabola 

$$ax^2 + bx + c $$

the line of symmetry is 

$$x = \frac{-b}{2a}$$

when you get this value substitute it for the max height

(c) you need to find then the height is 0.... 

so let H(t) = 0 and solve for x... maybe the general quadratic formula is easiest...