If the system of equations (λ-1) x+(λ-4) y+λ z=5; λ x+(λ-1) y+(λ-4) z=7; (λ+1) x+(λ+2) y-(λ+2) z=9 has infinitely many solutions, then λ^2+λ is equal…

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