College

Choose the correct simplification and demonstration of the closure property given:

[tex]
(2x^3 + x^2 - 4x) - (9x^3 - 7x^3 + 4x^2 - 4x)
[/tex]

A. [tex]-7x^3 + 4x^2 - 4x[/tex], may or may not be a polynomial

B. [tex]-7x^3 + 4x^2 - 4x[/tex], is a polynomial

C. [tex]11x^3 - 2x^2 - 4x[/tex], may or may not be a polynomial

D. [tex]11x^3 - 2x^2 - 4x[/tex], is a polynomial

Answer :

Let's simplify the given expression and demonstrate the closure property:

The expression is: [tex]\((2x^3 + x^2 - 4x) - (9x^3) - (-7x^3 + 4x^2 - 4x)\)[/tex].

To simplify, we need to:

1. Distribute the negative sign to the terms inside the parentheses.

2. Combine like terms.

Start with the expression:

1. Distribute the negative signs:
[tex]\[
(2x^3 + x^2 - 4x) - 9x^3 + 7x^3 - 4x^2 + 4x
\][/tex]

2. Combine like terms:
- For [tex]\(x^3\)[/tex]: [tex]\(2x^3 - 9x^3 + 7x^3 = 0x^3 = 0\)[/tex]
- For [tex]\(x^2\)[/tex]: [tex]\(x^2 - 4x^2 = -3x^2\)[/tex]
- For [tex]\(x\)[/tex]: [tex]\(-4x + 4x = 0x = 0\)[/tex]

The simplified expression is:
[tex]\[
-3x^2
\][/tex]

Conclusion: The result [tex]\(-3x^2\)[/tex] is a polynomial, showing that the closure property of polynomials holds because the subtraction of two polynomials results in another polynomial. Thus, the correct simplification is [tex]\(-3x^2\)[/tex], and it is indeed a polynomial.