What is the equation of the graph line when written in standard form

What is the value of the expression below? (81^2)^1/8

Ten members of balin's soccer team ran warm ups for practice. each member ran the same distance. their combined distance was 5/6 of a mile. to find the distance that each member ran, balin wrote the expression below.

What adds to be the bottom number but also multiplies to be the top number with 8 on the bottom and 15 on top