I too think you are getting something wrong here. Those formulae don't seem to make a hell of a lot of sense either, what is Std T? do you mean SAT/RAT/EAT or ISA?
Like Fred has said, you can calculate temperature at a given FL and give ISA deviation, but you wouldn't normally calculate FL from Temp unless it was some sort of derived exam question relating to Met and lapse rates, as FL is a position relative to pressure.