Some of the steps in the derivation of the quadratic formula are shown. step 3: –c b^2/4a=a(x^2 b/ax b^2/4a62) step 4a: –c b^2/4a=a(x b/2a)^2 step 4b: -4ac/4a b2/4a=a(x b/2a)^2 which best explains or justifies step 4b? -factoring a polynomial -multiplication property of equality -converting to a common denominator -addition property of equality