If the system of equations
\( (\lambda - 1)x + (\lambda - 4)y + \lambda z = 5 \)
\( \lambda x + (\lambda - 1)y + (\lambda - 4)z = 7 \)
\( (\lambda + 1)x + (\lambda + 2)y - (\lambda + 2)z = 9 \)
has infinitely many solutions, then \( \lambda^{2} + \lambda \) is equal to: