College

What is the product?

[tex]\left(7x^2\right)\left(2x^3+5\right)\left(x^2-4x-9\right)[/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 of the expression [tex]\((7x^2)(2x^3 + 5)(x^2 - 4x - 9)\)[/tex], we will go through the step-by-step multiplication of these polynomials. Here’s how you can do it:

1. Distribute the First Part: Start by distributing [tex]\(7x^2\)[/tex] into the first polynomial [tex]\((2x^3 + 5)\)[/tex].
- Multiply [tex]\(7x^2 \times 2x^3\)[/tex] to get [tex]\(14x^5\)[/tex].
- Multiply [tex]\(7x^2 \times 5\)[/tex] to get [tex]\(35x^2\)[/tex].

So, the product of the first two parts is:
[tex]\[
14x^5 + 35x^2
\][/tex]

2. Multiply by the Second Polynomial: Now, take the result from the first step and distribute it into the second polynomial [tex]\((x^2 - 4x - 9)\)[/tex].

- Multiply [tex]\(14x^5 \times x^2\)[/tex] to get [tex]\(14x^7\)[/tex].
- Multiply [tex]\(14x^5 \times (-4x)\)[/tex] to get [tex]\(-56x^6\)[/tex].
- Multiply [tex]\(14x^5 \times (-9)\)[/tex] to get [tex]\(-126x^5\)[/tex].

- Multiply [tex]\(35x^2 \times x^2\)[/tex] to get [tex]\(35x^4\)[/tex].
- Multiply [tex]\(35x^2 \times (-4x)\)[/tex] to get [tex]\(-140x^3\)[/tex].
- Multiply [tex]\(35x^2 \times (-9)\)[/tex] to get [tex]\(-315x^2\)[/tex].

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

3. Final Answer: After combining and simplifying all the terms, the complete expanded product is:
[tex]\[
14x^7 - 56x^6 - 126x^5 + 35x^4 - 140x^3 - 315x^2
\][/tex]

So the product of the given polynomials is:
[tex]\[
\boxed{14x^7 - 56x^6 - 126x^5 + 35x^4 - 140x^3 - 315x^2}
\][/tex]