Answer: Ana will hit the water after 3 seconds.
Explanation:
The exercise gives you the following function which models Anna's height above the water (in meters) after diving "x" seconds:

You can rewrite the function with
:

In order to calculate the number of seconds Ana will hit the water after diving, the procedure is:
- Substitute
into the function:

- Solve for "x".
By the Zero Product Property, you know that if
, then
or
.
Then you get:

- Choose the positive value (
)
Then, Ana will hit the water after 3 seconds.