1. **State the problem:** Simplify the expression $$15x - 8x - 9$$ and determine the sign of the terms in the answer. 2. **Identify like terms:** The terms $$15x$$ and $$-8x$$ are like terms because they both contain $$x$$. 3. **Combine like terms:** Use the rule for addition and subtraction of like terms: $$15x - 8x = (15 - 8)x = 7x$$ 4. **Rewrite the expression:** After combining like terms, the expression becomes: $$7x - 9$$ 5. **Determine the signs:** The term $$7x$$ is positive because $$7$$ is positive. The term $$-9$$ is negative because of the minus sign. 6. **Answer:** The simplified expression is $$7x - 9$$, where $$7x$$ is positive and $$-9$$ is negative. The two negatives in the original expression do not make the entire answer negative; only the $$-9$$ term is negative.