The Chronicles of the Three Kingdoms was the official and authoritative historical text compiled by Chen Shou[?] during the Chinese Jin Dynasty (265-420) on the period of Three Kingdoms. Its Chinese title is San Guo Zhi (三國志pinyin san1 guo2 zhi4) or San-Kuo Chih (Wade-Giles)
... 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 sides, ...