In mathematics, a Hamiltonian path in a graph is a path that visits each vertex precisely once. A Hamiltonian cycle is a cycle which visits each vertex once and only once.
This type of path is named after William Rowan Hamilton who invented a puzzle, now known as Hamilton's puzzle, about the construction of such paths.
... 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 ...