1. **State the problem:** We have a rectangular pool where the length is 2 meters shorter than twice its width. We need to write an expression for the perimeter and then find the perimeter. 2. **Define variables:** Let the width be $w$ meters. 3. **Express the length:** The length $L$ is given as $L = 2w - 2$. 4. **Recall the perimeter formula for a rectangle:** $$P = 2(L + w)$$ 5. **Substitute the length expression into the perimeter formula:** $$P = 2((2w - 2) + w)$$ 6. **Simplify inside the parentheses:** $$P = 2(3w - 2)$$ 7. **Distribute the 2:** $$P = 6w - 4$$ 8. **Interpretation:** The perimeter depends on the width $w$. If you know $w$, plug it in to find the perimeter. **Final expression for the perimeter:** $$P = 6w - 4$$