He multiplied the exponents.
Work Step by Step
From the final expression, we see that he ends up with 3/5 as an exponent. However, when two identical bases are multiplied, their exponents are added, not multiplied.
You can help us out by revising, improving and updating this answer.Update this answer
After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.