\[\frac{(a + 1)^{2} - 6a + 4}{a} =\]
\[= \frac{a^{2} + 2a + 1 - 6a + 4}{a} =\]
\[= \frac{a^{2} - 4a + 5}{a} = a - 4 + \frac{5}{a};\]
\[a = \pm 1;\ \pm 5.\]
\[Ответ:a = \pm 1;a = \pm 5.\]