Respuesta :

GCF would be : 3mn <===

Solutions 

[tex]3m^2n+12mn^2[/tex] 

[tex]3m^2n=3mn * m[/tex] 

[tex]12mn^2 = 3mn * 4[/tex] 

[tex]3m^2n;12mn^2 = 3mn[/tex]

[tex]=3mn[/tex]