Factor completely: 9x3 + 9x2y - 4x - 4y

[tex]9x^3 + 9x^2y - 4x - 4y[/tex]

[tex] = 9x^2(x + y) -4(x + y)[/tex]

[tex] = (x +y)(9x^2-4)[/tex]

[tex] = (x +y)(3x - 2)(3x + 2)[/tex]