Question 765666
{{{8^-1s^-3t/(2s^-1t)^-5}}}
={{{(1/8)(1/s^3)(t)(1/2^5)(s^5)(1/t^5)}}}
={{{(1/8*1/32)(s^2)(1/t^4)}}}
={{{(1/256)(s^2)(1/t^4)}}}
={{{s^2/256t^4}}}
;)