Question 134134
Note that (-)^n = (+) when n is even
and (-)^n = (-) when  n is odd
{{{(3s^2t)(-2st^2)^2/(-4st)^3(-2st)}}}
{{{(3s^2t)(4s^2t^4)/(-64s^3t^3)(-2st)}}}
{{{12s^4t^5 / 128s^4t^4}}}
{{{3t / 32}}} answer