线性方程组3x1?x2+x3＝0x1+λx2+x3＝0λx1+x2+x3＝0有非零解，则λ=______

Question

线性方程组3x1?x2+x3＝0x1+λx2+x3＝0λx1+x2+x3＝0有非零解，则λ=______．