College

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], follow these steps:

1. Identify Like Terms: The polynomials given are [tex]\(7x^3 - 4x^2\)[/tex] and [tex]\(2x^3 - 4x^2\)[/tex]. Notice that both polynomials have terms with [tex]\(x^3\)[/tex] and [tex]\(x^2\)[/tex].

2. Add the Coefficients of the Like Terms:
- For the [tex]\(x^3\)[/tex] terms:
- You have [tex]\(7x^3\)[/tex] from the first polynomial and [tex]\(2x^3\)[/tex] from the second polynomial.
- Add these coefficients: [tex]\(7 + 2 = 9\)[/tex].
- This gives you [tex]\(9x^3\)[/tex].

- For the [tex]\(x^2\)[/tex] terms:
- You have [tex]\(-4x^2\)[/tex] from both the first and the second polynomial.
- Add these coefficients: [tex]\(-4 + (-4) = -8\)[/tex].
- This gives you [tex]\(-8x^2\)[/tex].

3. Write the Resulting Polynomial:
- Combine the results from steps 2:
- You have [tex]\(9x^3\)[/tex] from the added [tex]\(x^3\)[/tex] terms and [tex]\(-8x^2\)[/tex] from the added [tex]\(x^2\)[/tex] terms.

The sum of the polynomials is [tex]\(9x^3 - 8x^2\)[/tex].

This matches the option [tex]\(9x^3 - 8x^2\)[/tex].