Both a and c are on the right side of the origin, so the absolute value of a+c can be decomposed into a+C.

Similarly, the absolute value of a can also be decomposed into a.

B is a negative number, so the absolute value of b is divided by-b.

To sum up, the result is C-B.

12.x-3.3-x

This is too simple, so I won't write the process. The reason is the same.