D.O.A. is a 1950movie that helped define the film noirgenre. The frantically-paced plot revolves around a doomed man's quest to find out who has murdered him - and why - before he dies.
... the common denominator is 4a2. We get
<math>\left(x+\frac{b}{2a}\right)^2=\frac{-4ac+b^2}{4a^2}=\frac{b^2-4ac}{4a^2}.</math>
Taking square roots ...