Applying C₁ → C₁ + C₂ + C₃ + C₄, we get,

Now, applying R₂ → R₂ – R₁, R₃ → R₃ – R₁, R₄ → R₄ – R₁, we get

Now, applying R₁ → R₁ + 3R₃

= (40)(8)(40)(40) = 512000

So, Δ = 512000