Centuries: 12th century - 13th century - 14th century
Decades: 1220s 1230s 1240s 1250s 1260s - 1270s - 1280s 1290s 1300s 1310s 1320s
Years: 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279
... left side is now a perfect square; it is the square of (x + b/(2a)). The right side can be written as a single ...