Given: Δ=∣∣
∣∣1xyz1yzx1zxy∣∣
∣∣
Minor of a13=M13=∣∣∣1y1z∣∣∣
⇒M13=1×z−1×y=z−y
Minor of a23=M23=∣∣∣1x1z∣∣∣
⇒M23=1×z−1×x=z−x
Minor of a33=M33=∣∣∣1x1y∣∣∣
⇒M33=1×y−1×x=y−x
Cofactor of a13=A13=(−1)1+3M13=(−1)4.(z−y)=z−y
Cofactor of a23=A23=(−1)2+3.M23=(−1)5.(z−x)=x−z
Cofactor of a33=A33=(−1)3+3.M33=(−1)6.(y−x)=y−x
Now,
Δ=a13A13+a23A23+a33A33
⇒Δ=yz(z−y)+zx(x−z)+xy(y−x)
⇒Δ=yz2−y2z+zx2−z2x+xy2−x2y
⇒Δ=(yz2−y2z)+(xy2−z2x)+(zx2−x2y)
⇒Δ=yz(z−y)+x(y2−z2)+x2(z−y)
⇒Δ=−yz(y−z)+x(y2−z2)−x2(y−z)
⇒Δ=−yz(y−z)+x(y+z)(y−z)−x2(y−z)
⇒Δ=(y−z)(−yz+x(y+z)−x2)
⇒Δ=(y−z)(z(x−y)−x(x−y))
⇒Δ=(x−y)(y−z)(z−x)
Therefore, the value of determinant is (x−y)(y−z)(z−x)