Simplify the expression: (3x² + 2x) - (x² - x).

To simplify the expression (3x² + 2x) - (x² - x), start by distributing the negative sign across the second set of parentheses. This changes the expression to:

3x² + 2x - x² + x.

Next, combine like terms. First, look at the x² terms: you have 3x² from the first part and -x² from the second part. This results in:

3x² - x² = 2x².

Now, look at the x terms: you have 2x from the first part and +x from the second part. This results in:

2x + x = 3x.

Combining these results, the simplified expression becomes:

2x² + 3x.

Thus, this choice accurately captures the final result due to the proper application of distributing the negative sign and combining like terms, leading to the expression being correctly simplified.