Question

b. (4x2y – 7xy3)(4x2y + 7xy3)​

Answer 1

Ejemplo :

$(ab - cd)(ab + cd) = {ab}^{2} - {cd}^{2}$

Entonces :

$(4 {x}^{2}y - 7x {y}^{3} )(4 {x}^{2}y + 7x {y}^{3}) \\ {(4 {x}^{2} y)}^{2} - {(7x {y}^{3}) }^{2} = 16 {x}^{4} {y}^{2} - 49 {x}^{2} {y}^{6}$