Respuesta :
factors of 9:
1, 9, 3
factors of 21:
1, 21, 3, 7
3 is greatest Common factor.
Divide both numbers by three and put three outside the bracket
3(3+7)
1, 9, 3
factors of 21:
1, 21, 3, 7
3 is greatest Common factor.
Divide both numbers by three and put three outside the bracket
3(3+7)
