Redirected from 647 BC
Decades: 690s BC 680s BC 670s BC 660s BC 650s BC - 640s BC - 630s BC 620s BC 610s BC 600s BC 590s BC
Significant People
... left side is now a perfect square; it is the square of (x + b/(2a)). The right side can be written as a single fraction; the c ...