Applying, C₁→C₁ + C₂ + C₃, we have,

Taking, (3x + λ) common, we get

Applying, R₂→R₂ – R₁, R₃→R₃ – R₁, we get,

= λ²(3x + λ)

So, Δ = λ²(3x + λ)