Centuries: 2nd century - 3rd century - 4th century
Decades: 210s - 220s - 230s - 240s - 250s - 260s - 270s - 280s - 290s - 300s - 310s
Years: 260 261 262 263 264 265 266 267 268 269
Events:
... sides, we get <math>x=\frac{-b}{2a}\pm\frac{\sqrt{b^2-4ac}}{2a}=\frac{-b\pm\sqrt{b^2-4ac}}{2a}.</math> Generalizations The formula and its proof ...