Question 35705
Factor:
1) {{{9x^2 - 16y^2}}} This is the difference of two squares and can be factored as follows:
{{{A^2 - B^2 = (A+B)(A-B)}}} Applying this to your problem:
{{{9x^2 - 16y^2 = (3x)^2 - (4y)^2}}} = {{{(3x+4y)(3x-4y)}}}

2) {{{3x^2 - 2x - 8}}}
The factors of 3x^2 are:(3x)(x)
The factors of -8 are: (-1)(8) or (-2)(4) or (2)(-4)
Try {{{(3x+4)(x-2) = 3x^2-6x+4x-8}}}= {{{3x^2-2x-8}}} 
The factors are: {{{(3x+4)(x-2)}}}

3) {{{3x^2+12x+12}}}
The factors of 3x are:(3x)(x)
The factor of 12 are: (1)(12) or (2)(6) or (3)(4)
Try {{{(3x+6)(x+2) = 3x^2+6x+6x+12}}}={{{3x^2+12x+12}}}
The factors are: {{{(3x+6)(x+2)}}}