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'll combine like terms from each polynomial.

1. Combine the [tex]\(x^3\)[/tex] terms:
- The first polynomial has [tex]\(7x^3\)[/tex].
- The second polynomial has [tex]\(2x^3\)[/tex].
- Adding these together: [tex]\(7x^3 + 2x^3 = 9x^3\)[/tex].

2. Combine the [tex]\(x^2\)[/tex] terms:
- The first polynomial has [tex]\(-4x^2\)[/tex].
- The second polynomial also has [tex]\(-4x^2\)[/tex].
- Adding these together: [tex]\(-4x^2 + (-4x^2) = -8x^2\)[/tex].

Now, we combine the results from the above steps to get the final sum of the polynomials:

- Combine the [tex]\(x^3\)[/tex] and [tex]\(x^2\)[/tex] terms: [tex]\(9x^3 - 8x^2\)[/tex].

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

Therefore, the correct answer is [tex]\(9x^3 - 8x^2\)[/tex], which corresponds to the choice [tex]\(9x^3 - 8x^2\)[/tex].