High School

What is the product?

[tex]\[ \left(7x^2\right)\left(2x^3+5\right)\left(x^2-4x-8\right) \][/tex]

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

B. [tex]\(14x^6 - 56x^5 - 81x^4 - 140x^3 - 315x^2\)[/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]\((7x^2)(2x^3 + 5)(x^2 - 4x - 8)\)[/tex], we will multiply these polynomial expressions step by step.

1. Multiply the first two expressions: [tex]\((7x^2)\)[/tex] and [tex]\((2x^3 + 5)\)[/tex].

- Distribute [tex]\(7x^2\)[/tex] across the terms inside the parentheses:
[tex]\[
7x^2 \cdot (2x^3 + 5) = (7x^2 \cdot 2x^3) + (7x^2 \cdot 5)
\][/tex]
- Calculate each term:
[tex]\[
7x^2 \cdot 2x^3 = 14x^5
\][/tex]
[tex]\[
7x^2 \cdot 5 = 35x^2
\][/tex]
- Combine these results:
[tex]\[
14x^5 + 35x^2
\][/tex]

2. Multiply the result with the third expression: [tex]\((x^2 - 4x - 8)\)[/tex].

- Distribute each term from [tex]\(14x^5 + 35x^2\)[/tex] to each term in [tex]\(x^2 - 4x - 8\)[/tex].

First, distribute [tex]\(14x^5\)[/tex]:

[tex]\[
14x^5 \cdot x^2 = 14x^7
\][/tex]

[tex]\[
14x^5 \cdot (-4x) = -56x^6
\][/tex]

[tex]\[
14x^5 \cdot (-8) = -112x^5
\][/tex]

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

[tex]\[
35x^2 \cdot x^2 = 35x^4
\][/tex]

[tex]\[
35x^2 \cdot (-4x) = -140x^3
\][/tex]

[tex]\[
35x^2 \cdot (-8) = -280x^2
\][/tex]

3. Combine all the terms obtained from distribution:

Collect all terms from each multiplication step:
[tex]\[
14x^7 - 56x^6 - 112x^5 + 35x^4 - 140x^3 - 280x^2
\][/tex]

This is the expanded polynomial product of the given expressions. So the product is:
[tex]\[
14x^7 - 56x^6 - 112x^5 + 35x^4 - 140x^3 - 280x^2
\][/tex]