The Council on Tall buildings and Urban Habitat (CTBUH) is an organization of Lehigh University's architecture department which has compiled the World's 100 Tallest Building rankings for the last 35 years.
... getting
<math>x^2+\frac{b}{a}x+\frac{b^2}{4a^2}=-\frac{c}{a}+\frac{b^2}{4a^2}.</math>
The left side is now a perfect square; it is the square of (x + ...