1. **Stating the problem:** We have a demand function for a good given by $$Q_d = 60 - 2P$$ where $Q_d$ is the quantity demanded and $P$ is the price. 2. **Find the quantity demanded when $P=0$ and $P=30$:** - When $P=0$, substitute into the demand function: $$Q_d = 60 - 2 \times 0 = 60$$ - When $P=30$, substitute into the demand function: $$Q_d = 60 - 2 \times 30 = 60 - 60 = 0$$ 3. **Graph the demand function:** The demand function is a linear equation: $$Q_d = 60 - 2P$$ - The intercept on the $Q_d$ axis is 60 (when $P=0$). - The intercept on the $P$ axis is when $Q_d=0$: $$0 = 60 - 2P \implies 2P = 60 \implies P = 30$$ 4. **Explain the relationship between price and quantity demanded:** The relationship is negative or inverse. This means: - When price $P$ increases, quantity demanded $Q_d$ decreases. - When price $P$ decreases, quantity demanded $Q_d$ increases. This reflects the basic consumer behavior principle that higher prices discourage buying, while lower prices encourage it. **Final answers:** - $Q_d = 60$ when $P=0$ - $Q_d = 0$ when $P=30$ This completes the solution.