Given choices:
(1) division property of equality
(2) factoring the binomial
(3)completing the square
(4)subtraction property of equality
Answer : (2) factoring the binomial
Step 1: \(-c = ax^2 + bx\)
Step 2:\(-c = a[x^2+\frac{b}{a} x]\)
In step 2, 'a' is taken out from \(ax^2 + bx\). when we take out 'a' we divide each term by 'a'. so it becomes \(a[x^2+\frac{b}{a} x]\)
'a' is factored out in step 2. we call it as factoring a binomial.
