First, use these rules of exponents to simplify the denominator:
#a = a^color(red)(1)# and #x^color(red)(a) xx x^color(blue)(b) = x^(color(red)(a) + color(blue)(b))#
#s^65/(s^-1 * s^-1 * s) =>#
#s^65/(s^color(red)(-1) * s^color(blue)(-1) * s^color(green)(1)) =>#
#s^65/s^(color(red)(-1)+color(blue)(-1)+color(green)(1)) =>#
#s^65/s^(color(red)(-1)-color(blue)(1)+color(green)(1)) =>#
#s^65/s^(-2+color(green)(1)) =>#
#s^65/s^-1#
Now, use this rule of exponents to complete the simplificcation:
#x^color(red)(a)/x^color(blue)(b) = x^(color(red)(a)-color(blue)(b))#
#s^color(red)(65)/s^color(blue)(-1) =>#
#s^(color(red)(65)-color(blue)(-1)) =>#
#s^(color(red)(65)+color(blue)(1)) =>#
#s^66#