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?
A=Kylie is correct.
B=Kylie correctly understood that it is a difference of squares, but she did not determine the product correctly.
C=Kylie did not understand that this is a perfect square trinomial, and she did not determine the product correctly.
D=Kylie determined the product correctly, but she did not understand that this is a perfect square trinomial.

Answer 1

The correct product should have been:
(–4x + 9)2 = (-4x)2 + 2(-4x)(9) + 9^2 = 16x6 - 72x +81
The result is a trinomial and not a binomial nor a difference of two squares.

So, the answer is:
C = Kylie did not understand that this is a perfect square trinomial, and she did not determine the product correctly.

Answer 2

Answer: C

Step-by-step explanation: Kyle is not correct because it is not a diference of 2 squares, but a perfect square trinomial.

(-4x + 9)² = (9 - 4x)² = 9² - 2.9.4x + (4x)² = 81 - 72x + 16x²