Question 403260
Please, write if I don't understand correct your problem
{{{root(16,(-7)^16)}}}
Use formulas {{{root(n,a^n)=abs(a)}}}, if n is EVEN number
___________{{{root(n,a^n)=a}}}, if n is ODD number
.
{{{root(16,(-7)^16)=abs(-7)=7}}}