Decades: 730s 740s 750s 760s 770s - 780s - 790s 800s 810s 820s 830s
Years: 783 784 785 786 787 - 788 - 789 790 791 792 793
Births
Deaths
... in this case is (b/a)x, we must have y = b/(2a), so we add the square of b/(2a) to both sides, ...