Question

The Students' Conjectures Emily and Zach have two different polynomials to multiply: Polynomial product A: (4x2 – 4x)(x2 – 4) Polynomial product B: (x2 + x – 2)(4x2 – 8x)

Answer 1

Complete Question:

Emily and Zach have two different polynomials to multiply: Polynomial product A: (4x2 – 4x)(x2 – 4) Polynomial product B: (x2 + x – 2)(4x2 – 8x) They are trying to determine if the products of the two polynomials are the same. But they disagree about how to solve this problem.

Answer:

$A = B$

Step-by-step explanation:

See comment for complete question

Given

$A: (4x^2 - 4x)(x^2 - 4)$

$B: (x^2 + x - 2)(4x^2 - 8x)$

Required

Determine how they can show if the products are the same or not

To do this, we simply factorize each polynomial

For, Polynomial A: We have:

$A: (4x^2 - 4x)(x^2 - 4)$

Factor out 4x

$A: 4x(x - 1)(x^2 - 4)$

Apply difference of two squares on x^2 - 4

$A: 4x(x - 1)(x - 2)(x+2)$

For, Polynomial B: We have:

$B: (x^2 + x - 2)(4x^2 - 8x)$

Expand x^2 + x - 2

$B:(x^2 + 2x - x - 2)(4x^2- 8x)$

Factorize:

$B:(x(x + 2) -1(x + 2))(4x^2- 8x)$

Factor out x + 2

$B:(x -1) (x + 2)(4x^2- 8x)$

Factor out 4x

$B:(x -1) (x + 2)4x(x- 2)$

Rearrange

$B: 4x(x - 1)(x - 2)(x+2)$

The simplified expressions are:

$A: 4x(x - 1)(x - 2)(x+2)$ and  

$B: 4x(x - 1)(x - 2)(x+2)$

Hence, both polynomials are equal

$A = B$