\[x^{2} - 4x - 32 = x^{2} - 4x + 4 - 36 =\]
\[= (x - 2)^{2} - 6^{2} =\]
\[= (x - 2 - 6)(x - 2 + 6) =\]
\[= (x - 8)(x + 4).\]