High School

Which of the following shows the polynomial below written in descending order?

[tex] x^3 - x + 9x^7 + 4 + 3x^{11} [/tex]

A. [tex] 3x^{11} + 9x^7 - x + 4 + 5 [/tex]

B. [tex] 3x^{11} + 9x^7 + 5x^3 - x + 4 [/tex]

C. [tex] 4 + 3x^{11} + 9x^7 + 5x^3 - x [/tex]

D. [tex] 9x^7 + 5x^3 + 4 + 3x^{11} - x [/tex]

Answer :

Sure, let's solve the problem step-by-step.

Question: Which of the following shows the polynomial below written in descending order?

Given polynomial:
[tex]\[ x^3 - x + 9x^7 + 4 + 3x^{11} \][/tex]

To write the polynomial in descending order, we need to arrange the terms by the power of [tex]\(x\)[/tex] in decreasing order.

1. Identify the term with the highest power of [tex]\(x\)[/tex]:
- [tex]\(3x^{11}\)[/tex] (highest power, 11)

2. Next, find the term with the next highest power of [tex]\(x\)[/tex]:
- [tex]\(9x^7\)[/tex] (next highest power, 7)

3. Then, look for the term with the next highest power of [tex]\(x\)[/tex]:
- [tex]\(x^3\)[/tex] (next highest power, 3)

4. The linear term:
- [tex]\(-x\)[/tex] (x has power 1)

5. Lastly, the constant term:
- [tex]\(4\)[/tex] (constant term, no [tex]\(x\)[/tex])

Arrange these terms in descending order of their exponents:

[tex]\[ 3x^{11} + 9x^7 + x^3 - x + 4 \][/tex]

Now, let's compare this arranged polynomial with the given options:

A. [tex]\(3x^{11} + 9x^7 - x + 4 + 5\)[/tex]
- This is incorrect because the terms are not all present, and an extraneous "+ 5" is included.

B. [tex]\(3x^{11} + 9x^7 + 5x^3 - x + 4\)[/tex]
- This is incorrect because the term [tex]\(x^3\)[/tex] should not have a coefficient of 5.

C. [tex]\(4 + 3x^{11} + 9x^7 + 5x^3 - x\)[/tex]
- This is incorrect because the terms are not in descending order.

D. [tex]\(9x^7 + 5x^3 + 4 + 3x^{11} - x\)[/tex]
- This is incorrect because [tex]\(3x^{11}\)[/tex] should come first, and the coefficient for [tex]\(x^3\)[/tex] is incorrect and should not precede [tex]\(x^3\)[/tex] or be 5.

The correct answer is:

[tex]\[ 3x^{11} + 9x^7 + x^3 - x + 4 \][/tex]

So the correct choice is:

B. [tex]\(3x^{11} + 9x^7 + x^3 - x + 4\)[/tex]