Respuesta :

Answer:

A

Step-by-step explanation:

[tex]\huge \sf༆ Answer ༄[/tex]

Let's solve ~

  • [tex] \sf {x}^{2} - 10xy + 21 {y}^{2} [/tex]

  • [tex] \sf {x}^{2} - 7xy - 3xy + 21 {y}^{2} [/tex]

  • [tex] \sf x(x - 7y) - 3y(x - 7y)[/tex]

  • [tex] \sf( x - 7y)(x - 3y)[/tex]

Hence, the correct choice is ~ A