High School

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------------------------------------------------ **Multiplication of Polynomials Quiz**

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^8 - 126x^5 + 35x^4 - 140x^3 - 315x^2[/tex]

D. [tex]14x^{12} - 182x^6 + 35x^4 - 455x^2[/tex]

Answer :

Let's find the product of the given polynomials step by step:

We have three polynomials to multiply:

1. [tex]\( 7x^2 \)[/tex]
2. [tex]\( 2x^3 + 5 \)[/tex]
3. [tex]\( x^2 - 4x - 9 \)[/tex]

### Step 1: Multiply the first two polynomials

First, multiply [tex]\( 7x^2 \)[/tex] by [tex]\( 2x^3 + 5 \)[/tex]:

- Distribute [tex]\( 7x^2 \)[/tex] across each term in the polynomial [tex]\( 2x^3 + 5 \)[/tex]:

[tex]\[
\begin{align*}
(7x^2) \times (2x^3) &= 14x^5, \\
(7x^2) \times 5 &= 35x^2.
\end{align*}
\][/tex]

Combine these results:

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

### Step 2: Multiply the result with the third polynomial

Now, multiply [tex]\( 14x^5 + 35x^2 \)[/tex] by [tex]\( x^2 - 4x - 9 \)[/tex].

- Distribute each term of [tex]\( 14x^5 + 35x^2 \)[/tex] across [tex]\( x^2 - 4x - 9 \)[/tex]:

For [tex]\( 14x^5 \)[/tex]:

[tex]\[
\begin{align*}
(14x^5) \times (x^2) &= 14x^7, \\
(14x^5) \times (-4x) &= -56x^6, \\
(14x^5) \times (-9) &= -126x^5.
\end{align*}
\][/tex]

For [tex]\( 35x^2 \)[/tex]:

[tex]\[
\begin{align*}
(35x^2) \times (x^2) &= 35x^4, \\
(35x^2) \times (-4x) &= -140x^3, \\
(35x^2) \times (-9) &= -315x^2.
\end{align*}
\][/tex]

### Step 3: Combine all the terms

Now, combine all the like terms from the results above:

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

That's the final product of the given multiplication:

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

However, the given options did not correctly match our calculated polynomial, showing the results will not fit any of the provided options correctly. Make sure to double-check the problem statement and options.