Centuries: 9th century - 10th century - 11th century
Decades: 880s - 890s - 900s - 910s - 920s - 930s - 940s - 950s - 960s - 970s - 980s
Years: 930 931 932 933 934 935 936 937 938 939
... + 2xy + y2. Since "2xy" in this case is (b/a)x, we must have y = b/(2a), so we add the square of b/(2a) to both sides, ...