Haven't watched the whole thing, but scrolling down and reading his closing makes me not want to watch it. He complicates the simple procedure "Completing the Square" (http://en.wikipedia.org/wiki/Completing_the_square). Take half of the b coefficient, square it, and add it to both sides gives x^2 + 10x + 25 = 64 or the completed square (x+5)^2 = 64 or x+5 = 8 or x=3.