Simplest of Equations

(I.) A guy whose crush thinks he's dating his best friend, who also has a rival. (II.) A girl who has a lady boner for a certain friend of hers (who is completely smitten with their mutual friend) and a homosexual guy. (III.) A guy who's in love with a girl who dated (then broke up with) a douche bag.

But really, once it's all sorted out, they'll find out that these factors can be found in the simplest equations.