Decades: 710s BC 700s BC 690s BC 680s BC 670s BC - 660s BC - 650s BC 640s BC 630s BC 620s BC 610s BC
Significant People
... (In a field of characteristic 2, the element 2a is zero and it is impossible to divide by it.) The symbol <math>\pm \sqrt {b^2-4ac}</math> in the formula ...