Let a = b.
Hence, a^2 = ab.
So, 2a^2-2ab = a^2 - ab
2(a^2-ab) = 1(a^2-ab)
I showed this to two maths teachers at my school who couldn't figure this... Let's see how you guys fare.
This one can be found on Wikipedia if my memory is correct. It is indeed a division by zero.
Indeed. I had a high school teacher. I was interested in his knowledge. I asked him something a bit advanced (modular arithmetic). He looked at me, blinked, and told me to finish my worksheet. Lame. I don't recall having any math teacher that actually was interested in maths.high school teachers are mostly idiots who only know what the school expects them to teach.