1. **State the problem:** Simplify the expression $$(3a+2a)(5a-7b)$$. 2. **Combine like terms inside the parentheses:** $$3a + 2a = 5a$$ So the expression becomes: $$(5a)(5a - 7b)$$ 3. **Use the distributive property (FOIL method) to expand:** $$5a \times 5a = 25a^2$$ $$5a \times (-7b) = -35ab$$ 4. **Write the expanded expression:** $$25a^2 - 35ab$$ 5. **Final answer:** The simplified form of $$(3a+2a)(5a-7b)$$ is: $$25a^2 - 35ab$$