Respuesta :

1.6) 12 and 9 have 3 as a common factor. 8 and 6 have 2 as a common factor
  3x(4x +3) +2(4x +3)

1.7) (3x+2)(4x+3)


2.5) (3x² +6x) + (4x +8)

2.6) 3 and 4 are common factors.
  3x(x+2) +4(x+2)

2.7) (3x+4)(x+2)