Respuesta :

Answer:

[tex]3(x+y)(x+y)[/tex]

Step-by-step explanation:

[tex]3x(x+y)+3y(x+y)[/tex]

[tex]3x^{2} +6xy+3y^{2}[/tex]

[tex]3(x+y)(x+y)[/tex]

hope this helps.....