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 given functions, follow these detailed steps:

Given the expressions:
[tex]\[ \left(7 x^2\right), \quad \left(2 x^3 + 5\right), \quad \left(x^2 - 4 x - 9\right) \][/tex]

1. Multiply the first two expressions:

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

Distribute \(7x^2\) across each term in the second expression:

[tex]\[ 7x^2 \cdot 2x^3 + 7x^2 \cdot 5 = 14x^5 + 35x^2 \][/tex]

2. Multiply the resulting expression by the third expression:

[tex]\[ (14x^5 + 35x^2) \cdot (x^2 - 4x - 9) \][/tex]

Now distribute each term in the first polynomial across each term in the second polynomial:

- First, multiply \(14x^5\):

[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 \(35x^2\):

[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:

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

Therefore, the product of the given functions is:

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

The correct answer is:
[tex]\[ \boxed{14 x^7 - 56 x^6 - 126 x^5 + 35 x^4 - 140 x^3 - 315 x^2} \][/tex]