Decades: 1220s 1230s 1240s 1250s 1260s - 1270s - 1280s 1290s 1300s 1310s 1320s
Years: 1266 1267 1268 1269 1270 - 1271 - 1272 1273 1274 1275 1276
Births
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... parabola described by the quadratic equation touches the x-axis in a single point.) If the discriminant is positive, then there are two different solutions x, both of ...