1. **State the problem:** Simplify the algebraic expression $3a + 7b + 2a - 4b$. 2. **Identify like terms:** Like terms are terms that have the same variable raised to the same power. Here, $3a$ and $2a$ are like terms, and $7b$ and $-4b$ are like terms. 3. **Combine like terms:** - Combine $3a$ and $2a$: $$3a + 2a = (3 + 2)a = 5a$$ - Combine $7b$ and $-4b$: $$7b - 4b = (7 - 4)b = 3b$$ 4. **Write the simplified expression:** $$5a + 3b$$ This is the simplified form of the given expression.