Centuries: 2nd century - 3rd century - 4th century
Decades: 190s 200s 210s 220s 230s - 240s - 250s 260s 270s 280s 290s
Years: 237 238 239 240 241 - 242 - 243 244 245 246 247
Births
Deaths
... the equation. The formula reads <math> x=\frac{-b \pm \sqrt {b^2-4ac}}{2a} </math> The term b2 – 4ac is called the discriminant of the quadratic ...