Usamos el ( a - b )² = a² - 2ab + b ²
[tex]( {x}^{3} {)}^{2} - 2 {x}^{3} \times 8 {y}^{9} + (8 {y}^{9} {)}^{2} [/tex]
simplificamos multiplicando los exponentes
[tex] {x}^{6} - 2 {x}^{3} \times 8 {y}^{9} + (8 {y}^{9} {)}^{2} [/tex]
calculamos
[tex] {x}^{6} - 16 {x}^{3} {y}^{9} + (8 {y}^{9} {)}^{2} [/tex]
elevan el factor a la potencia
[tex] {x}^{6} - 16 {x}^{3} {y}^{9} + 64 {y}^{18} [/tex]