High School

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 given expressions [tex]\((7x^2)(2x^3 + 5)(x^2 - 4x - 9)\)[/tex], we'll break it down in a step-by-step manner.

1. Distribute the first term: Start by multiplying [tex]\(7x^2\)[/tex] with each term of the second expression [tex]\((2x^3 + 5)\)[/tex]:

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

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

This gives the expression: [tex]\(14x^5 + 35x^2\)[/tex].

2. Multiply the result by the third term: Now we multiply [tex]\((14x^5 + 35x^2)\)[/tex] by [tex]\((x^2 - 4x - 9)\)[/tex].

- Distribute [tex]\(14x^5\)[/tex] across [tex]\((x^2 - 4x - 9)\)[/tex]:

[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]

- Distribute [tex]\(35x^2\)[/tex] across [tex]\((x^2 - 4x - 9)\)[/tex]:

[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: Add all the terms obtained from the multiplication:

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

This simplifies to:

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

Thus, the final product of the expression is:

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