What is the sum of the polynomials?

[tex]\left(7x^3 - 4x^2\right) + \left(2x^3 - 4x^2\right)[/tex]

A. [tex]5x^3[/tex]

B. [tex]9x^3[/tex]

C. [tex]5x^3 - 8x^2[/tex]

D. [tex]9x^3 - 8x^2[/tex]

Answer :

To find the sum of the polynomials [tex]\((7x^3 - 4x^2)\)[/tex] and [tex]\((2x^3 - 4x^2)\)[/tex], follow these steps:

1. Identify Like Terms:
- The first polynomial, [tex]\(7x^3 - 4x^2\)[/tex], has terms [tex]\(7x^3\)[/tex] and [tex]\(-4x^2\)[/tex].
- The second polynomial, [tex]\(2x^3 - 4x^2\)[/tex], has terms [tex]\(2x^3\)[/tex] and [tex]\(-4x^2\)[/tex].

2. Add the Like Terms:
- Combine the cubic terms: [tex]\(7x^3\)[/tex] from the first polynomial and [tex]\(2x^3\)[/tex] from the second polynomial. Adding these gives [tex]\(7x^3 + 2x^3 = 9x^3\)[/tex].
- Combine the quadratic terms: [tex]\(-4x^2\)[/tex] from the first polynomial and [tex]\(-4x^2\)[/tex] from the second polynomial. Adding these gives [tex]\(-4x^2 + (-4x^2) = -8x^2\)[/tex].

3. Write the Resulting Polynomial:
- The sum of the polynomials is the sum of the combined like terms. Therefore, the resulting polynomial is [tex]\(9x^3 - 8x^2\)[/tex].

Thus, the sum of the polynomials [tex]\((7x^3 - 4x^2)\)[/tex] and [tex]\((2x^3 - 4x^2)\)[/tex] is [tex]\(9x^3 - 8x^2\)[/tex].