Cory writes the polynomial [tex]x^7 + 3x^5 + 3x + 1[/tex]. Melissa writes the polynomial [tex]x^7 + 5x + 10[/tex].

Is there a difference between the degree of the sum and the degree of the difference of the polynomials?

A. Adding their polynomials together or subtracting one polynomial from the other both result in a polynomial with degree 7.

B. Adding their polynomials together or subtracting one polynomial from the other both result in a polynomial with degree 5.

C. Adding their polynomials together results in a polynomial with degree 14, but subtracting one polynomial from the other results in a polynomial with degree 5.

D. Adding their polynomials together results in a polynomial with degree 7, but subtracting one polynomial from the other results in a polynomial with degree 5.



Answer :

To determine the degree of the sum and the difference of Cory's and Melissa's polynomials, let's analyze each step carefully.

First, let's write down the polynomials:
- Cory's polynomial: [tex]\(p_1(x) = x^7 + 3x^5 + 3x + 1\)[/tex]
- Melissa's polynomial: [tex]\(p_2(x) = x^7 + 5x + 10\)[/tex]

### Step-by-Step Solution:

#### 1. Sum of the Polynomials
Adding [tex]\(p_1(x)\)[/tex] and [tex]\(p_2(x)\)[/tex]:

[tex]\[ p_1(x) + p_2(x) = (x^7 + 3x^5 + 3x + 1) + (x^7 + 5x + 10) \][/tex]

Combine like terms:

[tex]\[ = (x^7 + x^7) + 3x^5 + (3x + 5x) + (1 + 10) \][/tex]
[tex]\[ = 2x^7 + 3x^5 + 8x + 11 \][/tex]

The highest power of [tex]\(x\)[/tex] in this polynomial is [tex]\(x^7\)[/tex], so the degree of the sum is 7.

#### 2. Difference of the Polynomials
Subtracting [tex]\(p_2(x)\)[/tex] from [tex]\(p_1(x)\)[/tex]:

[tex]\[ p_1(x) - p_2(x) = (x^7 + 3x^5 + 3x + 1) - (x^7 + 5x + 10) \][/tex]

Distribute the negative sign and combine like terms:

[tex]\[ = x^7 - x^7 + 3x^5 + 3x - 5x + 1 - 10 \][/tex]
[tex]\[ = 0 + 3x^5 - 2x - 9 \][/tex]

The highest power of [tex]\(x\)[/tex] in this polynomial is [tex]\(x^5\)[/tex], so the degree of the difference is 5.

#### 3. Comparing the Degrees
- The degree of the sum of the polynomials is 7.
- The degree of the difference of the polynomials is 5.

There is a difference in the degrees of the sum and the difference of the polynomials.

Conclusion: Adding their polynomials together results in a polynomial with degree 7, but subtracting one polynomial from the other results in a polynomial with degree 5. Hence, there is a difference in the degrees.