Choose the correct sum of the polynomials [tex]\left(3x^3 - 5x - 8\right) + \left(5x^3 + 7x + 3\right)[/tex].

A. [tex]2x^3 - 12x - 11[/tex]
B. [tex]2x^3 + 12x - 5[/tex]
C. [tex]8x^3 + 2x + 5[/tex]
D. [tex]8x^3 + 2x - 5[/tex]



Answer :

To find the sum of the polynomials [tex]\((3x^3 - 5x - 8) + (5x^3 + 7x + 3)\)[/tex], follow these steps:

1. Write down the given polynomials:
- The first polynomial is [tex]\(3x^3 - 5x - 8\)[/tex].
- The second polynomial is [tex]\(5x^3 + 7x + 3\)[/tex].

2. Align the polynomials by their like terms, which are the same powers of [tex]\(x\)[/tex]:

[tex]\[ \begin{array}{r} 3x^3 + 0x^2 - 5x - 8 \\ + \ 5x^3 + 0x^2 + 7x + 3 \\ \end{array} \][/tex]

3. Add the like terms separately:

- For the [tex]\(x^3\)[/tex] term: [tex]\(3x^3 + 5x^3 = 8x^3\)[/tex]
- For the [tex]\(x^2\)[/tex] term: There are no [tex]\(x^2\)[/tex] terms, so the sum is [tex]\(0x^2\)[/tex].
- For the [tex]\(x\)[/tex] term: [tex]\(-5x + 7x = 2x\)[/tex]
- For the constant term: [tex]\(-8 + 3 = -5\)[/tex]

4. Combine the results into one polynomial:

[tex]\[ 8x^3 + 0x^2 + 2x - 5 \][/tex]

5. Simplify the polynomial by removing the zero coefficient term:

[tex]\[ 8x^3 + 2x - 5 \][/tex]

Therefore, the correct sum of [tex]\((3x^3 - 5x - 8) + (5x^3 + 7x + 3)\)[/tex] is [tex]\(8x^3 + 2x - 5\)[/tex].

Hence, the correct answer is:
[tex]\[ 8x^3 + 2x - 5 \][/tex]