\(x^3-4x^2-11x+30\)
\(=x^3-2x^2-2x^2+4x-15x+30\)
\(=x^2\left(x-2\right)-2x\left(x-2\right)-15\left(x-2\right)\)
\(=\left(x-2\right)\left(x^2-2x-15\right)\)
\(=\left(x-2\right)\left(x^2-5x+3x-15\right)\)
\(=\left(x-2\right)\left[x\left(x-5\right)+3\left(x-5\right)\right]\)
\(=\left(x-5\right)\left(x-2\right)\left(x+3\right)\)