\[\left( x^{2} - 4x + 3 \right) \cdot \ *\ = x^{3} - 3x^{2} - x + 3\]
\[\ x^{3} - 3x^{2} - x + 3 =\]
\[= x^{2}(x - 3) - (x - 3) =\]
\[= (x - 3)\left( x^{2} - 1 \right) =\]
\[= (x - 3)(x - 1)(x + 1)\]
\[x^{2} - 4x + 3 = x^{2} - x - 3x + 3 =\]
\[= x(x - 1) - 3 \cdot (x - 1) =\]
\[= (x - 1)(x - 3)\]
\[(x - 3)(x - 1) \cdot \ *\ =\]
\[= (x - 3)(x - 1)(x + 1)\]
\[\Longrightarrow \ *\ = (x + 1).\]