The comments on the Cheezburger LOLShirt of the Weekend are priceless.  Please read the whole thread.

Here’s an example of the “debate”:

“So the large lines that underline the whole thing symbolize having performed a step (operation).

9x – 7i > 3(3x-7u)

step 1: distribute the 3 to the 3x-7u result: 9x – 7i > 9x – 21u

step 2: subtract 9x from both sides. result: -7i > -21u

the people combined two steps into one, which is where people get confused. breaking it into two separate steps:

step 3: divide both sides by 7 result: -i > -3u (to see why the next step works, imagine that i = 2 and u = 1… then it would say -2 > -3, which is true.)

step 4: divide both sides by -1. result: i < 3u you can see that the inequality is only still true for the pretend values of i=2 and u=1 if you flip the sign. with the flip you get 2 3 which is false!

and yes, you can have inequalities with i. super cute :)

(via LOLmart Shirts: Love Equation – LOL Shirts - Funny LOLcat meme t-shirts)