a: =x^3+6x^2+12x+8-x^3-3x^2-3x-1
=3x^2+9x+7
b: =x^3-9x^2+27x-27-x(x^2-6x+9)
=x^3-9x^2+27x-27-x^3+6x^2-9x
=-3x^2+18x-27
c: \(=x^3+3x^2+3x+1-x^3-x^2-2x^2-4x\)
=-x+1
d: \(=x^3+3x^2+3x+1-x^2+16-x^3\)
=2x^2+3x+17
e: =x(x^2-25)-x^3+15x^2-75x+125+100x
=x^3-25x-x^3+15x^2+25x+125
=15x^2+125
f: =x^3+125-x^3-15x^2-75x-125
=-15x^2-75x