to find the root, you must find out each numbers and variables squared
for example, rt(64) = 8, for 8 x 8 = 64
rt(m^2) is m, for m x m = m^2
rt(n^3) is n√n, for n x n x n = n^3, and only pairs of number (or variables) can be take out
rt(p^4) is p^2, for p x p x p x p = p^4
so your answer is
8mnp²√n
8p²mn√n is your answer
hope this helps
