To factor $ x^{3}-8x^{2}+8x-64 $ we can use factoring by grouping:
Group $ \color{blue}{ x^{3} }$ with $ \color{blue}{ -8x^{2} }$ and $ \color{red}{ 8x }$ with $ \color{red}{ -64 }$ then factor each group.
$$ \begin{aligned} x^{3}-8x^{2}+8x-64 = ( \color{blue}{ x^{3}-8x^{2} } ) + ( \color{red}{ 8x-64 }) &= \\ &= \color{blue}{ x^{2}( x-8 )} + \color{red}{ 8( x-8 ) } = \\ &= (x^{2}+8)(x-8) \end{aligned} $$