Step number 2 contains the mistake. The correct expression for that step is 5^2 * (3^-1)^(-2).
In step 2, Tim made a mistake by not applying the exponent rule correctly. The exponent rule states that when you raise a power to another power, you multiply the exponents.
So, when raising (3^-1) to the power of -2, we need to multiply the exponents. (-1) * (-2) = 2. Therefore, the correct expression for that step is 5^2 * 3^2.
To explain it further, in step 1, Tim correctly evaluated 3^8/3^9 as 3^(-1) because when you divide powers with the same base, you subtract the exponents. Then, in step 2, he should have applied the exponent rule correctly to get 3^(-1)^(-2) = 3^2.
The correct expression for step 2 is 5^2 * 3^2.