Centuries: 2nd century - 3rd century - 4th century
Decades: 210s 220s 230s 240s 250s - 260s - 270s 280s 290s 300s 310s
Years: 257 258 259 260 261 - 262 - 263 264 265 266 267
Births
Deaths
... 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 of both ...