Simplify: 10 - 3(2 + 1).

To simplify the expression 10 - 3(2 + 1), start by solving the operation inside the parentheses. Here, you have (2 + 1), which equals 3. This transforms the expression into 10 - 3(3).

Next, you will perform the multiplication. Multiply 3 by 3 to get 9. Now your expression looks like 10 - 9.

The final step is to subtract 9 from 10, which gives you 1. Therefore, the simplified result is indeed 1.