Question

calcule :

(2y ^ 3 - 6y - 18) + (6y ^ 2 + 2y - 2​

Answer 1

$(2 {y}^{3} - 6y - 18) + (6 {y}^{3} + 2y - 2) \\ \\ 2 {y}^{3} - 6y - 18 + {6y}^{2} + 2y - 2 \\ \\ ( - 6 + 2)y \\ - 4y \\ \\ 2 {y}^{3} - 4y - 18 + 6 {y}^{2} - 2 \\ \\ - (18 + 2) \\ - 20 \\ \\ 2 {y}^{3} - 4y - 20 + 6 {y}^{2} \\ \\ 2 {y}^{3} + 6 {y}^{2} - 4y - 20 \\ \\ \red{ \: 2 {y}^{3} + 6 {y}^{2} - 4y - 20}$