1. The problem asks for the expression of the area of a rectangle with width $9 - d$ and height $3$. 2. The formula for the area $A$ of a rectangle is: $$A = \text{width} \times \text{height}$$ 3. Substitute the given width and height into the formula: $$A = (9 - d) \times 3$$ 4. Use the distributive property to expand the brackets: $$A = 3 \times 9 - 3 \times d$$ $$A = 27 - 3d$$ 5. So, the expression for the area of the rectangle, fully expanded, is: $$27 - 3d$$ This means the area depends on the value of $d$, and as $d$ increases, the area decreases linearly.