/sci/ - Science & Math

I have some sort of mini quiz tomorrow for my calculus class. All I have to do is memorize a dumbed down version of the definition of Limit. Unfortunalty my backpack got locked in the student store which doesnt open until tomorrow morning after my math class.
I studied it the first day I got it and memorized almost all of it, but I need help in filling in the holes. It was four lines that went something like this

If f(x) approaches the number L
As x approaches the number ''a''
From both the left and the right
Then xxxxxxxxxxxxxxxxxxxxxxxxxxxx

I think the first 3 lines are correct but I can't seem to remember how the last line goes. Any help?