h(x) = -5(x+1)(x-3)

Question

What is the height of Ana above the water at the time of diving?

meters

 

 

How many seconds after diving will Ana hit the water?

seconds

 

 

 

P.S. i had to take out all the spaces because it was more than 160 characters so sorry, its a word problem

 

Ana dives into a pool off a springboard high dive. Her height above the water in meters h(x) is depended on time in seconds after diving, x, and can be modeled with  the function h(x) = -5(x+1) (x-3).

 

 

P.S.S. this is the problem that is above

Answer 1

Hi Berline,

 

If you graph this function you will see that it is a parabola opening downward: https://www.desmos.com/calculator/cklnfd8xzy ; (take a look)

 

To find the height of the diver at time of diving you really want to find h when x = 0.

 

h(x) = -5(0+1)(0-3) = 15

 

To find how long it takes to hit the water, you want to know what is x when h = 0

 

0 = -5(x+1)(x-3). That will be the case when x+1 = 0 or x - 3 = 0. That is when x = -1 or x = 3. Since we are dealing with time the -1 is rejected as an answer to the word problem.