1. **State the problem:** Solve the equation $$3(7z - 23) = 99$$ for the variable $z$. 2. **Use the distributive property:** Multiply 3 by each term inside the parentheses: $$3 \times 7z - 3 \times 23 = 99$$ which simplifies to $$21z - 69 = 99$$ 3. **Isolate the term with $z$:** Add 69 to both sides to move the constant term: $$21z - 69 + 69 = 99 + 69$$ $$21z = 168$$ 4. **Solve for $z$:** Divide both sides by 21: $$z = \frac{168}{21}$$ 5. **Simplify the fraction:** $$z = 8$$ **Final answer:** $$z = 8$$