To find Rajeev's new position after descending further, let's carefully examine each part of the problem step by step.
1. Initial Depth of Rajeev:
Rajeev starts at a depth of 12.6 feet below the surface of the water. Depths below the surface are considered negative relative to the surface, which means the initial position is:
[tex]\[
-12.6 \text{ feet}
\][/tex]
2. Additional Descent:
Rajeev then descends another 8.7 feet. Similarly, descending further below the surface is also considered a negative change in depth:
[tex]\[
-8.7 \text{ feet}
\][/tex]
3. Calculating New Position:
To find the new position, you need to add the additional descent to the initial depth, because Rajeev is moving further down:
[tex]\[
-12.6 + (-8.7)
\][/tex]
This can be simplified to:
[tex]\[
-12.6 - 8.7
\][/tex]
Therefore, the correct expression to find Rajeev's new position is:
[tex]\[
-12.6 - 8.7
\][/tex]
Hence, the correct option from the given answers is:
[tex]\[
\boxed{-12.6 - 8.7}
\][/tex]
