B. Neither/nor is the answer
The submarine is now 617.5 feet below sea level, or at -617.5 feet. the temperature is now at 65 9/20
you have to add the first values with the second values :)
This is a linear equation in x.
So you need to group like terms

Let us group the x terms on the Right Hand Side of the equation and the constant terms on the Left Hand Side.

We can now simplify

Now let us divide both sides by 3.

This implies that

or

Let us our answer



Good we are right