STACK has options for very fine control over simplification. Because there are so many options, this can appear complicated!
First, for questions like this I recommend turning question level simplification off, and turn off simplification in all potential response trees.
If you forbid * etc. in the input then students will get validation feedback. You _might_ want 25^(3+6) to be _wrong_ rather than invalid. You might also want to give 25^(3+6) some partial credit. E.g. a PRT could have two tests, (i) algebraic equivalence (or something more specific), and (ii) in the right "simplified" form.
Some notes on simplification are here.
https://docs.stack-assessment.org/en/Authoring/Authoring_quick_start_7/
and
https://docs.stack-assessment.org/en/CAS/Simplification/
I recommend looking at the answer test "Equality up to Associativity and Commutativity" here - that's what I'd probably use for this question: https://docs.stack-assessment.org/en/Authoring/Answer_tests_rules_based/
Chris
First, for questions like this I recommend turning question level simplification off, and turn off simplification in all potential response trees.
If you forbid * etc. in the input then students will get validation feedback. You _might_ want 25^(3+6) to be _wrong_ rather than invalid. You might also want to give 25^(3+6) some partial credit. E.g. a PRT could have two tests, (i) algebraic equivalence (or something more specific), and (ii) in the right "simplified" form.
Some notes on simplification are here.
https://docs.stack-assessment.org/en/Authoring/Authoring_quick_start_7/
and
https://docs.stack-assessment.org/en/CAS/Simplification/
I recommend looking at the answer test "Equality up to Associativity and Commutativity" here - that's what I'd probably use for this question: https://docs.stack-assessment.org/en/Authoring/Answer_tests_rules_based/
Chris