Cenni di Petro (Giovanni) Cimabue (c.1240-1302) was a Florentinepainter and creator of mosaics, better known as the artist who discovered Giotto and with him moved towards treating figures as individuals.
... 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 ...