Respuesta :

[tex] (3x^2+16x+9) + (-16x-12)[/tex]

Remove the brackets:
[tex] = 3x^2+16x+9 -16x-12[/tex]

Combine like terms:
[tex] = 3x^2- 3[/tex]

Take out common factor 3:
[tex] = 3(x^2- 1)[/tex]

Factorise (x² - 1):
[tex] = 3(x- 1)( x+ 1)[/tex]