Which of the following responses shows that polynomials form a closed system under multiplication?

(1 point)
Responses

14x3 ⋅ 5
14x3 ⋅ 5

x −−√ ⋅ (6x ⋅ −3)
x −−√ ⋅ (6x ⋅ −3)

x ⋅ 2x
x ⋅ 2x

3x24−1

1 answer

To determine which of the given responses shows that polynomials form a closed system under multiplication, we need to identify if the result of each multiplication operation yields a polynomial.

  1. Response: ( 14x^3 \cdot 5 )
    This results in \( 70x^3 \), which is a polynomial.

  2. Response: ( \sqrt{x} \cdot (6x \cdot -3) )
    This equates to \( -18x^{3/2} \), which is not a polynomial because it involves a non-integer exponent.

  3. Response: ( x \cdot 2x )
    This results in \( 2x^2 \), which is a polynomial.

  4. Response: ( 3x^{24} - 1 )
    This is already a polynomial.

Based on the above evaluations, the responses that demonstrate multiplication resulting in a polynomial (thus showing closure under multiplication) are:

  • \( 14x^3 \cdot 5 \)
  • \( x \cdot 2x \)

Both of these responses confirm that polynomials form a closed system under multiplication.