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 of the expression [tex]\(\left(7x^2\right)\left(2x^3+5\right)\left(x^2-4x-9\right)\)[/tex], we'll work through the calculation in a step-by-step manner.

1. First, distribute [tex]\((7x^2)\)[/tex] to the terms in [tex]\((2x^3 + 5)\)[/tex]:

Multiply [tex]\(7x^2\)[/tex] by each term in [tex]\((2x^3 + 5)\)[/tex]:

[tex]\[
(7x^2) \cdot (2x^3) = 14x^5
\][/tex]

[tex]\[
(7x^2) \cdot 5 = 35x^2
\][/tex]

So, we get: [tex]\(14x^5 + 35x^2\)[/tex].

2. Next, multiply the result by [tex]\((x^2 - 4x - 9)\)[/tex]:

We need to multiply [tex]\((14x^5 + 35x^2)\)[/tex] with [tex]\((x^2 - 4x - 9)\)[/tex]. Distribute each term from the first polynomial across each term in the second polynomial:

- Multiply [tex]\(14x^5\)[/tex] with each term:
[tex]\[
14x^5 \cdot x^2 = 14x^7
\][/tex]
[tex]\[
14x^5 \cdot (-4x) = -56x^6
\][/tex]
[tex]\[
14x^5 \cdot (-9) = -126x^5
\][/tex]

- Multiply [tex]\(35x^2\)[/tex] with each term:
[tex]\[
35x^2 \cdot x^2 = 35x^4
\][/tex]
[tex]\[
35x^2 \cdot (-4x) = -140x^3
\][/tex]
[tex]\[
35x^2 \cdot (-9) = -315x^2
\][/tex]

3. Combine all the terms from the multiplication:

The expanded product is:

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

This is the resultant polynomial from multiplying the given expressions.