Question: Solve the equation below using inverse operations. f - 9 = 22 Yul's work f - 9 = 22 - 9 - 9 f = 13 Yul solved the equation shown. What do you notice? He subtracted 9 when he should have added. He made a mistake when subtracting 9 from 22. He should have subtracted 22 from both sides instead of 9. He solved the equation correctly.

1. **State the problem:** Solve the equation $$f - 9 = 22$$ using inverse operations. 2. **Recall the rule:** To isolate the variable $$f$$, perform the inverse operation of subtracting 9, which is adding 9, on both sides of the equation. 3. **Check Yul's work:** Yul subtracted 9 from both sides: $$\begin{aligned} f - 9 &= 22 \\ -9 &\quad -9 \\ f &= 13 \end{aligned}$$ 4. **Analyze the step:** Subtracting 9 again on both sides is incorrect because it does not isolate $$f$$. Instead, it makes the equation $$f - 18 = 13$$ if done correctly, but Yul wrote $$f = 13$$ which is not correct. 5. **Correct solution:** Add 9 to both sides: $$\begin{aligned} f - 9 &= 22 \\ +9 &\quad +9 \\ f &= 22 + 9 \\ f &= 31 \end{aligned}$$ 6. **Conclusion:** Yul made a mistake when subtracting 9 from 22. The correct answer is $$f = 31$$. **Therefore, the correct option is:** "He made a mistake when subtracting 9 from 22."