D Question 7 1 pts Circle all facts/claims that were used in the proof of Proposition 1.2.3 (the Arithmetic- Geometric Mean Inequality). O The quadratic formula theorem O (x + y) = x2 + 2xy+ y for all real x, y O If 0 0 if and only if x and y have the same sign.Proposition 1.2.3 (The Arithmetic-Geometric Mean Inequality). For any two real numbers x and y, x . y cty 2 , and equality holds iff (if and only if) x = y. 2 If, in addition, x, y 2 0, then vay cty 2