Which operation shows that polynomials are a closed system under addition? (1 point)
Responses
(5x2+2x+1)+(−2x2+6x+4)=(5x2−2x2)+(2x+6x)+(1+4)
left parenthesis 5 x squared plus 2 x plus 1 right parenthesis plus left parenthesis negative 2 x squared plus 6 x plus 4 right parenthesis equals left parenthesis 5 x squared minus 2 x squared right parenthesis plus left parenthesis 2 x plus 6 x right parenthesis plus left parenthesis 1 plus 4 right parenthesis
(5x2+2x+1)+(−2x2+6x+4)=3x2+8x+5
left parenthesis 5 x squared plus 2 x plus 1 right parenthesis plus left parenthesis negative 2 x squared plus 6 x plus 4 right parenthesis equals 3 x squared plus 8 x plus 5
(5x2+2x+1)+(−2x2+6x+4)=(−2x2+2x+4)+(5x2+6x+1)
left parenthesis 5 x squared plus 2 x plus 1 right parenthesis plus left parenthesis negative 2 x squared plus 6 x plus 4 right parenthesis equals left parenthesis negative 2 x squared plus 2 x plus 4 right parenthesis plus left parenthesis 5 x squared plus 6 x plus 1 right parenthesis
(5x2+2x+1)+(−2x2+6x+4)=−3x2+8x−3