High School

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]\((7x^3 - 4x^2) + (2x^3 - 4x^2)\)[/tex], we can follow these steps:

1. Identify Like Terms:
- In each polynomial, we have terms with [tex]\(x^3\)[/tex] and terms with [tex]\(x^2\)[/tex].
- Polynomial 1: [tex]\(7x^3 - 4x^2\)[/tex]
- Polynomial 2: [tex]\(2x^3 - 4x^2\)[/tex]

2. Add the Coefficients of Like Terms:
- For [tex]\(x^3\)[/tex] terms:
- Add the coefficients of [tex]\(x^3\)[/tex] from both polynomials: [tex]\(7 + 2 = 9\)[/tex].
- For [tex]\(x^2\)[/tex] terms:
- Add the coefficients of [tex]\(x^2\)[/tex] from both polynomials: [tex]\(-4 + (-4) = -8\)[/tex].

3. Write the Resultant Polynomial:
- Combine the results from step 2 to form the new polynomial:
- The sum is [tex]\(9x^3 - 8x^2\)[/tex].

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