8 It is given that \(\frac { 2 + 3 a \mathrm { i } } { a + 2 \mathrm { i } } = \lambda ( 2 - \mathrm { i } )\), where \(a\) and \(\lambda\) are real constants.
Show that \(3 a ^ { 2 } + 4 a - 4 = 0\).
Hence find the possible values of \(a\) and the corresponding values of \(\lambda\).