Which operation shows that polynomials are a closed system under subtraction? (1 point)

(2x ^ 2 + 6x + 1) - (3x ^ 2 + 3x + 9) = (2x ^ 2 + 6x - 4) - (3x ^ 2 + 3x + 4)

(2x ^ 2 + 6x + 1) - (3x ^ 2 + 3x + 9) = - x ^ 2 + 3x - 8

(2x ^ 2 + 6x + 1) - (3x ^ 2 + 3x + 9) = 5x ^ 2 + 9x + 10

(2x ^ 2 + 6x + 1) - (3x ^ 2 + 3x + 9) = 2x ^ 2 + 6x + 1 - 3x ^ 2 - 3x - 9

The correct answer is:

(2x ^ 2 + 6x + 1) - (3x ^ 2 + 3x + 9) = (2x ^ 2 + 6x - 4) - (3x ^ 2 + 3x + 4)

The correct option that shows that polynomials are a closed system under subtraction is:

(2x^2 + 6x + 1) - (3x^2 + 3x + 9) = 2x^2 + 6x + 1 - 3x^2 - 3x - 9