Given function must form Indeterminant form for finding value of C
= [x^5c (1+ 7/x + 2/x^5 )^c - x]
… (Take x^5 common from first bracket)
=x[x^5c-1 ( 1+ 7/x + 2/x^5)^c - 1]
… (Take X common from both brackets)
7/x and 2/x^5 can be neglected because as limits tends to infinity.
for indeterminant for (0.infinity)
5C-1 = 0