Skinnskatteberg is a municipality in central Sweden, in the county of Västmanland. The municipality covers an area of 661.9 km². Of the total population of 4855, 2480 are male, and 2375 are female. The population density of the community is 7 inhabitants per km².
... that will make it a perfect square trinomial of the form x2 + 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 ...