This is a list of divisions of the United States Army past and present. Armored, cavalry, and infantry are each numbered in their own sequences, and are thus grouped; the airborne and mountain divisions are numbered with the other infantry.
... add the square of b/(2a) to both sides, 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 ...