1. **State the problem:** Determine if the relation given by the set of ordered pairs \((2, 3), (-18, 9), (2, -9), (0, 15)\) is a function. 2. **Recall the definition of a function:** A relation is a function if every input (x-value) corresponds to exactly one output (y-value). This means no x-value can be paired with more than one y-value. 3. **Analyze the given pairs:** The x-values are \(2, -18, 2, 0\). 4. **Check for repeated x-values:** The x-value \(2\) appears twice with different y-values \(3\) and \(-9\). 5. **Conclusion:** Since the x-value \(2\) corresponds to two different y-values, the relation is **not** a function. **Final answer:** No, this relation is not a function.