Question

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

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

Answer 1

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

Explanation:

Answer 2

Given:

The given expression is:

`(-4x+9)^2`

According to Kylie,

`(-4x+9)^2=(-4x)^2+(9)^2`

`(-4x+9)^2=16x^2+81`

To find:

The correct statement for Kylie's explanation.

Solution:

We have,

`(-4x+9)^2`

According to the perfect square trinomial
`(a+b)^2=a^2+2ab+b^2`.

`(-4x+9)^2=(-4x)^2+2(-4x)(9)+(9)^2`

`(-4x+9)^2=16x^2-72x+81`

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

Therefore, the correct option is C.