a) \(x^3+2x^2+2x+1\)
\(=\left(x^3+x^2\right)+\left(x^2+2x+1\right)\)
\(=x^2\left(x+1\right)+\left(x+1\right)^2\)
\(=\left(x^2+x+1\right)\left(x+1\right)\)
b) \(x^3-4x^2+12x-27\)
\(=\left(x^3-27\right)-\left(4x^2-12x\right)\)
\(=\left(x-3\right)\left(x^2+3x+9\right)-4x.\left(x-3\right)\)
\(=\left(x-3\right).\left[\left(x^2+3x+9\right)-4x\right]\)
\(=\left(x-3\right).\left(x^2-x+9\right)\)