\(=4^3-\left(x-1\right)^3=\left(4-x+1\right)\left[16+4.\left(x-1\right)+\left(x-1\right)^2\right]=\left(5-x\right)\left(16+4x-4+x^2-2x+1\right)=\left(5-x\right)\left(x^2+2x+13\right)\)
\(=\left[\left(4-x+1\right)\right]\left[4^2+4\left(x-1\right)+\left(x-1\right)^2\right]\)
\(=\left(5-x\right)\left(x^2-2x+1+4x-4+16\right)\)
\(=\left(5-x\right)\left(x^2+2x+13\right)\)