\(x^3-x^2-14x+24\)
\(=x^3+4x^2-5x^2-20x+6x+24\)
\(=\left(x^3+4x^2\right)-\left(5x^2+20x\right)+\left(6x+24\right)\)
\(=x^2\left(x+4\right)-5x\left(x+4\right)+6\left(x+4\right)\)
\(=\left(x^2-5x+6\right)\left(x+4\right)\)
\(=\left(x^2-2x-3x+6\right)\left(x+4\right)\)
\(=\left[x\left(x-2\right)-3\left(x-2\right)\right]\left(x+4\right)\)
\(=\left(x-2\right)\left(x-3\right)\left(x+4\right)\)