Centuries: 2nd century - 3rd century - 4th century
Decades: 160s - 170s - 180s - 190s - 200s - 210s - 220s - 230s - 240s - 250s - 260s
Years: 210 211 212 213 214 215 216 217 218 219
Events:
... 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 it ...