Final answer:
The expression 87¹/⁹ is equivalent to the ninth root of 87, or √⁹87.
Step-by-step explanation:
The expression 87¹/⁹ can be rewritten in the form of a root to show the ninth root of 87. When expressing this in radical form, the base remains inside the radical, and the exponent becomes the index of the root. Therefore, the expression is equivalent to n√87, where n represents the index of the root, which in this case is 9. So, 87¹/⁹ is equivalent to √⁹87 or the ninth root of 87.