Question

simplify2

Answer 1

D

Answer 2

that is not a real number

Answer 3

Using the same method I've been doing for all the other root problems you've asked:
With square roots we found doubles. With cube roots we would find triples. With 4th roots... we find quadruples.

4th_root(-81)
4th_root(-3 * 3 * 3 * 3)
We can take ONE three out, getting
3 * 4th_root(-1)

Going past this is probably beyond the scope of this assignment, so I won't go any further. Note that since you can't take even numbered roots of negative numbers and get real answers, so the answer is D.