Hank made a mistake in Step 1. The correct operation to isolate the term involving \( x \) in the equation \( 25 = \frac{x}{4} - 9 \) would be to add 9 to both sides of the equation. Instead, Hank incorrectly arrived at \( 16 = \frac{x}{4} \) which implies he subtracted 9. Therefore, the correct response is:
Hank made a mistake in Step 1. The first step needed to solve this correctly would be to add 9 to both sides of the equation. Hank subtracted 9 instead of adding 9.