Columbia Records introduces the 33 1/3 LP (“long playing”) record at New York's Waldorf-Astoria Hotel[?], featuring 25 minutes of music per side, compared to the four minutes per side of the 78 rpm record, the previous standard.
... formula reads
<math>
x=\frac{-b \pm \sqrt {b^2-4ac}}{2a}
</math>
The term b2 – 4ac is called the discriminant of the quadratic equation, because ...