
This meme uses Albert Einstein’s image to show the excitement of figuring out a smart math trick. It’s about solving \lim_{x\to a} \frac{x^2-a^2}{x-a}, which looks hard at first because it gives \frac{0}{0} when x=a. By factoring x^2-a^2 into (x-a)(x+a), you can cancel (x-a) and get \lim_{x\to a}(x+a). That equals a+a=2a. The joke is about the “I’m a genius!” feeling students get when they first see this trick work.