code class$=$"asciimath"$>$x $($x$-(1)/($x$))^(3$n$)($ n $)5$ : The $5^($th $)$ term from the end in the expansion of $($x$-(1)/($x$))^(3$n$)$ in increasing power of xn is a positive integer$^(3$n$)$C$\_(5)$x$^(3$n$-10)($b$)^(-3$n$)$C$\_(5)$x$^(3$n$-10)($e$)^(3$n$)$C$\_(4)$x$^(3$n$-8)($d$)(-1)^(3$n$-43$n$)$C$\_(3$n$-4)$x$^(8-3$n$)$