Decades: 180s - 190s - 200s - 210s - 220s - 230s - 240s - 250s - 260s - 270s - 280s
Years: 230 231 232 233 234 235 236 237 238 239
Events:
... quadratic formula is derived by the method of completing the square[?]. <math>ax^2+bx+c=0</math> Dividing our quadratic equation by a, w ...