Question

Hank’s teacher asked him to verify that the product (y – 3)(y2 + 3y + 9) is a difference of cubes. He used the distributive property to multiply the binomial times the trinomial. Before simplifying, his product was a polynomial of the form y3 + 3y2 + ay – 3y2 – ay – 27. What is the value of a in the polynomial?

Answer 1

C.

Explanation:

edg.

Answer 2

a = 9

Explanation:

expand (y - 3)(y² + 3y + 9)

= y³ + 3y² + 9y - 3y² - 9y - 27

compare the coefficients of like terms with

y³ + 3y² + ay - 3y² - ay - 27

ay = 9y and - ay = - 9y ⇒ a = 9