High School

What is the product?

[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]\((7x^2)(2x^3 + 5)(x^2 - 4x - 9)\)[/tex], we will expand the expression step by step.

1. Distribute the first two factors: Start by multiplying the polynomial [tex]\((7x^2)\)[/tex] with [tex]\((2x^3 + 5)\)[/tex].

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

[tex]\[
= 14x^5 + 35x^2
\][/tex]

Now, we have our intermediate result: [tex]\(14x^5 + 35x^2\)[/tex].

2. Multiply the result with the third factor: Next, take the polynomial [tex]\(14x^5 + 35x^2\)[/tex] and multiply it with [tex]\((x^2 - 4x - 9)\)[/tex].

- First, multiply [tex]\(14x^5\)[/tex] by each term in the second polynomial:

[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]

- Then, multiply [tex]\(35x^2\)[/tex] by each term in the second polynomial:

[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: Finally, add all these products together to get the final expanded polynomial.

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

Thus, the product of the given expression is:

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