Solution:
The fish is swimming 5 feet under the water surface will be represented below as
![=-5ft](https://img.qammunity.org/2023/formulas/mathematics/college/qdhkd10mf15b41tusgrfvdr6rh6mam7jei.png)
5 feet take negative because the fish is swimming below the surface of the water.
The fish then descends 10 feet down,This can be represented below also
![=-10ft](https://img.qammunity.org/2023/formulas/mathematics/college/obdniinezkw63g066hxyzfohgq3bv881vo.png)
10 feet take negative because the fish descends
The fish then ascends (goes up) by 4 feet
This can be represented below as
![=+4ft](https://img.qammunity.org/2023/formulas/mathematics/college/aqpntjribwwdouhxf46pxkdx2ui3aqd5qw.png)
Concept:
To calculate the depth of the fish means to add up all the depth
By applying the concept, we will have
![\begin{gathered} =(-5ft)+(-10ft)+(+4ft) \\ =-5ft-10ft+4ft \\ =-15ft+4ft \\ =-11ft \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/mk5438uhtu3clrnzde98ri4ps515yn4a06.png)
Hence,
The fish is 11 feet under the water surface