Decades: 1330s 1340s 1350s 1360s 1370s - 1380s - 1390s 1400s 1410s 1420s 1430s
Years: 1383 1384 1385 1386 1387 - 1388 - 1389 1390 1391 1392 1393
Births
Deaths
... fraction; the common denominator is 4a2. 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 ...