It depends on the publisher's license agreement and copyright policy. Some publishers allow instructors to use their test questions and PowerPoints for educational purposes, while others do not. It is always best to check the license agreement that came with the textbook or to contact the publisher directly to find out what you can and cannot do.
If you do want to make changes to the PowerPoints, you should also check the license agreement to see if that is allowed. In some cases, you may be allowed to modify the PowerPoints for your own use, but you may not be allowed to distribute the modified versions to others.
Regardless of the license agreement, it is important to respect the intellectual property rights of the publisher and to only use the materials in accordance with the terms and conditions outlined in the license agreement.
Answer written by ChatGPT, a language model developed by OpenAI. Edited by Stephanie Towery, Copyright & Open Access Initiative Librarian.