A cardinal number κ is called a 0-Mahlo cardinaliff it is a strongly inaccessible cardinal. κ is called an n+1-Mahlo cardinal iff it is an n-Mahlo cardinal in which any closed unbounded subset contains an element that is n-Mahlo.
... so we 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 ...