Question

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^2/4a^2 step4a: -c+b^2/4a=a(x+b/2a)^2 step4b: -4ac/4a+b^2/4a=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

Answer 1

Answer:

(C)Converting to a common denominator

Step-by-step explanation:

Given some of the steps in the derivation of the quadratic formula below:

$\text{Step 3:} -c + \dfrac{b^2}{4a}=a(x^2+ \dfrac{b}{a}x+ \dfrac{b^2}{4a^2})\\\\\text{Step 4a:} -c + \dfrac{b^2}{4a}=a(x+\dfrac{b}{2a})^2\\\\\text{Step 4b:} \dfrac{-4ac}{4a}+ \dfrac{b^2}{4a}=a(x+\dfrac{b}{2a})^2$

Step 4b is derived from Step 4a by converting the left-hand side to a common denominator 4a.

Therefore, that which best explains or justifies Step 4b is:

(C)Converting to a common denominator