\(\dfrac{x^3-4x^2-x+4}{x^3-7x^2+14x-8}\)
\(=\dfrac{x^2\cdot\left(x-4\right)-\left(x-4\right)}{\left(x-2\right)\left(x^2+2x+4\right)-7x\left(x-2\right)}\)
\(=\dfrac{\left(x-4\right)\left(x-1\right)\left(x+1\right)}{\left(x-2\right)\left(x^2-5x+4\right)}\)
\(=\dfrac{x+1}{x-2}\)