Question

Which operation shows that polynomials are a closed system under addition

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

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

(2x^2+6x+1)+(3x^2+9)=(2x^2+3x2)+(6x3x)+(1+9

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

Answer 1

The correct operation that shows that polynomials are a closed system under addition is:

(2x^2+6x+1)+(3x^2+9)=(5x^2+15x+10)