Social facts are things that force individuals to do certain behaviors. The term was coined by a French sociologistEmile Durkheim to describe human behavior that is not attributed to their individual characteristic but to social facts.
... 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 sides, ...