College

What is the product of the following expression?

[tex]\[(7x^2)(2x^3 + 5)(x^2 - 4x - 9)\][/tex]

A. [tex]\(14x^5 - x^4 - 46x^3 - 58x^2 - 20x - 45\)[/tex]

B. [tex]\(14x^6 - 56x^5 - 91x^4 - 140x^3 - 315x^2\)[/tex]

C. [tex]\(14x^7 - 56x^6 - 126x^5 + 35x^4 - 140x^3 - 315x^2\)[/tex]

D. [tex]\(14x^{12} - 182x^6 + 35x^4 - 455x^2\)[/tex]

Answer :

To find the product [tex]\((7x^2)(2x^3 + 5)(x^2 - 4x - 9)\)[/tex], we'll break it down step by step.

1. Multiply the first two factors:

- Start by multiplying [tex]\(7x^2\)[/tex] and [tex]\((2x^3 + 5)\)[/tex].
- Distribute [tex]\(7x^2\)[/tex] over each term in [tex]\((2x^3 + 5)\)[/tex]:
[tex]\[
7x^2 \times 2x^3 = 14x^5
\][/tex]
[tex]\[
7x^2 \times 5 = 35x^2
\][/tex]
- Combine these results to get:
[tex]\[
14x^5 + 35x^2
\][/tex]

2. Multiply the result with the third factor:

- Now multiply [tex]\((14x^5 + 35x^2)\)[/tex] by [tex]\((x^2 - 4x - 9)\)[/tex].
- Distribute each term of [tex]\((14x^5 + 35x^2)\)[/tex] over [tex]\((x^2 - 4x - 9)\)[/tex].

3. Expand Step-by-step:

[tex]\[
14x^5 \times x^2 = 14x^7
\][/tex]
[tex]\[
14x^5 \times -4x = -56x^6
\][/tex]
[tex]\[
14x^5 \times -9 = -126x^5
\][/tex]

- Next, distribute [tex]\(35x^2\)[/tex]:

[tex]\[
35x^2 \times x^2 = 35x^4
\][/tex]
[tex]\[
35x^2 \times -4x = -140x^3
\][/tex]
[tex]\[
35x^2 \times -9 = -315x^2
\][/tex]

4. Combine All Terms:

- Now, combine all these terms:
[tex]\[
14x^7 - 56x^6 - 126x^5 + 35x^4 - 140x^3 - 315x^2
\][/tex]

This expression matches the second option given in the multiple-choice answers. Therefore, the product is:

[tex]\[
14x^7 - 56x^6 - 126x^5 + 35x^4 - 140x^3 - 315x^2
\][/tex]