a: \(\Leftrightarrow x^3+4x^2+4x+\left(a-4\right)x^2+\left(4a-16\right)x+\left(4a-16\right)+\left(-4a+12\right)x-4a+12⋮x^2+4x+4\)
=>-4a+12=0
=>a=3
b: \(\Leftrightarrow x^3-2x^2-2x+2x^2-4x-4+\left(a+6\right)x+b+4⋮x^2-2x-2\)
=>a+6=0 và b+4=0
=>a=-6; b=-4