You are supposed to know a few rules and laws concerning calculations of powers:

that means the negative sign of an exponent can be translated into a fraction with the numerator 1.

that means a fraction as exponent can be translated into a root. (Jhevon published recently a very impressive image about the (flower)power and it's root. Search for it)

Your problem becomes:

EDIT: I'm not quite certain but maybe this is the thread: http://www.mathhelpforum.com/math-he...t=flower+power