Answer:
3.
[tex]x^{2} - x - 12\\x^{2} - 4x + 3x -12\\x(x -4)+3(x-4)\\(x+3)(x-4)[/tex]
4.
[tex]x^{2} -8x +12\\x^{2} -6x -2x +12\\x(x-6)-2(x-6)\\(x-2)(x-6)\\[/tex]
