[tex]\implies {\blue {\boxed {\boxed {\purple {\sf { \:A. \:- 8 {b}^{4} + 10 {b}^{3} + 10b}}}}}}[/tex]
[tex]\large\mathfrak{{\pmb{\underline{\red{Step-by-step\:explanation}}{\red{:}}}}}[/tex]
[tex](7b + 7 {b}^{3} - 6 {b}^{4} ) + (3 {b}^{3} + 3b - 2 {b}^{4} )[/tex]
➼[tex] \: 7b + 7 {b}^{3} - 6 {b}^{4} + 3 {b}^{3} + 3b - 2 {b}^{4} [/tex]
Combining like terms, we have
➼[tex] \: - 6 {b}^{4} - 2 {b}^{4} + 7 {b}^{3} + 3 {b}^{3} + 7b + 3b[/tex]
➼[tex] \: - 8 {b}^{4} + 10 {b}^{3} + 10b[/tex]
[tex]\large\mathfrak{{\pmb{\underline{\orange{Mystique35 }}{\orange{❦}}}}}[/tex]
