1. **State the problem:** Simplify the expression $3(x-9)$. 2. **Formula used:** Use the distributive property $a(b+c) = ab + ac$. 3. **Apply the distributive property:** Multiply 3 by each term inside the parentheses: $$3(x-9) = 3 \times x - 3 \times 9$$ 4. **Simplify:** $$3x - 27$$ 5. **Final answer:** The simplified expression is $3x - 27$.