If the solution of the system of simultaneous equations
\[
\frac{1}{x} + \frac{2}{y} - \frac{3}{z} = 1, \quad
\frac{2}{x} - \frac{4}{y} + \frac{3}{z} = 1, \quad
\frac{3}{x} + \frac{6}{y} - \frac{6}{z} = 4
\]
is \( x = \alpha, y = \beta, z = \gamma \), then the value of \( \alpha^2 + \gamma^2 \) is: