Answer :

To find the sum of [tex]\(-356.1\)[/tex] and [tex]\(258.6\)[/tex], follow these steps:

1. Understand the Problem: You need to add two numbers: [tex]\(-356.1\)[/tex] and [tex]\(258.6\)[/tex].

2. Perform the Addition:
- Start by observing the signs of the numbers. One number is negative ([tex]\(-356.1\)[/tex]) and the other is positive ([tex]\(258.6\)[/tex]).
- When adding a negative and a positive number, you effectively subtract the smaller absolute value from the larger absolute value.
- So, you'll compute the difference between their absolute values:
[tex]\[
\text{Absolute difference} = |356.1| - |258.6| = 356.1 - 258.6
\][/tex]

3. Calculate the Difference:
- Subtract [tex]\(258.6\)[/tex] from [tex]\(356.1\)[/tex]:
[tex]\[
356.1 - 258.6 = 97.5
\][/tex]

4. Determine the Sign:
- Since the absolute value of [tex]\(-356.1\)[/tex] is greater than [tex]\(258.6\)[/tex], the result takes the sign of the larger absolute value, which is negative.

5. Write the Final Answer:
- Therefore, the sum of [tex]\(-356.1\)[/tex] and [tex]\(258.6\)[/tex] is [tex]\(-97.5\)[/tex].

So, the correct answer is [tex]\(-97.5\)[/tex].