Umbria is a hilly region in central Italy, spread over the provinces of Perugia and Terni. The region is named for the Umbri[?] tribe, who settled in the region in the 6th century BC. Their language was Umbrian, a relative of Latin.
... 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 sides, ...