Answer: -3.1 + (-0.35) is -3.45.
Explanation:
To find the decimal representation of the expression -3.1+(-0.35), you can add the two numbers together.
Start by lining up the decimal points:
```
-3.10
+ -0.35
```
Next, add the numbers together column by column, starting from the right side:
```
-3.10
+ -0.35
---------
-3.45
```
So, the decimal representation of -3.1 + (-0.35) is -3.45.