A few days ago
~ever stays red~

math help please!?

the height (in feet) of a punted football is given by

y= (-4/9x^2) + (24/9x) + 12

parenthesis are around the fractions

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?

c. how long is the punt?

Top 1 Answers
A few days ago
Kia

Favorite Answer

a. When ball is punted x is 0

y = (-4/9x^2) + (24/9x) + 12

y = (-4/9(0)^2) + (24/9(0)) + 12

y = 0 + 0 + 12

y = 12

b. Get the derivative of y and solve for x to find out how far the ball has traveled when it reaches the maximum height

y’ = -8/9x + 24/9 = 0

-8/9x = -24/9

-8x = -24

x = -24/-8

x = 3

Now plug x into the original formula to find the maximum height:

y = (-4/9x^2) + (24/9x) + 12

y = (-4/9(3)^2) + (24/9(3)) + 12

y = (-4/9(9)) + (24/9(3)) + 12

y = (-4) + (8) + 12

y = 16

c. We can find the length of the punt by finding when the height is 0

(-4/9x^2) + (24/9x) + 12 = 0

4x^2 – 24x – 108 = 0

(4x – 36)(x + 3)

x + 3 = 0

x = -3

And

4x – 36 = 0

4x = 36

x = 36/4

x = 9

So the punt was 9 feet since -3 is not accepted

Sounds like one of my punts

I hope this helped

Kia

1