Question

Kylie explained that (–4x + 9)2 will result in a difference of squares because (–4x + 9)2 = (–4x)2 + (9)2 = 16x2 + 81. Which statement best describes Kylie’s explanation?

Answer 1

Kylie did not understand that this is a perfect square trinomial, and she did not determine the product correctly.

Explanation:

Answer 2

Kylie is wrong about the result since (–4x + 9)2 will result to a perfect square trinomal. Any binomial squared will always result to a perfect square trinomial.

And the expansion of the expression should be
(–4x + 9)2 = (-4x)2 + 2(-4x)(9) + 9^2
(–4x + 9)2 = 16x2 - 72x + 18

She missed doing the middle term in doing the multiplication