The system of equations

2x - y + z = 0

x - 2y + z = 0

λx y + 2z = 0

has infinite number of nontrivial solutions for

1. λ = 1
2. λ = 5
3. λ = -5
4. no real value for λ

there is no visible sign between the x term and the y term in the third equation. This question cannot be solved wothout that information. Sorry for the inconvenience but please repost the question.