Decades: 1150s 1160s 1170s 1180s 1190s - 1200s - 1210s 1220s 1230s 1240s 1250s
Years: 1203 1204 1205 1206 1207 - 1208 - 1209 1210 1211 1212 1212
Births
Deaths
... 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 bo ...