[tex]\qquad \qquad\huge \underline{\boxed{\sf Answer}}[/tex]
let's solve ~
[tex]\qquad \sf \dashrightarrow \: (6 {x}^{2} + 6x + 9) + ({x}^{2} + 2x)[/tex]
[tex]\qquad \sf \dashrightarrow \: 6 {x}^{2} + 6x + 9 + {x}^{2} + 2x[/tex]
[tex]\qquad \sf \dashrightarrow \: 6 {x}^{2} + {x}^{2} + 6x + 2x + 9[/tex]
[tex]\qquad \sf \dashrightarrow \: 7 {x}^{2} + 8x + 9[/tex]
