Decades: 1160s 1170s 1180s 1190s 1200s - 1210s - 1220s 1230s 1240s 1250s 1260s
Years: 1207 1208 1209 1210 1211 - 1212 - 1213 1214 1215 1216 1217
Births
Deaths
... 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 ...