This cache is a "follow-up" to my "X Marks the Spot"!! I received positive feedback and excitement from my Algebra I kiddos at school, so I decided to take my cache to the next level...QUADRATICS! Beware of muggles, though.
So, think back to "foiling" in your Algebra class. X really DOES mark the spot:
X2 - 9X + 20 = 0