Simplify `(a+b)(2a-3b+c)-(2a-3b)c.`

Explanation

To simplify the expression \((a+b)(2a-3b+c)-(2a-3b)c\), we will follow these steps:

### Step 1: Expand the first expression \((a+b)(2a-3b+c)\)

We will distribute \(a\) and \(b\) across the terms in the parentheses:

\[
(a+b)(2a-3b+c) = a(2a-3b+c) + b(2a-3b+c)
...