COMEDK2020MathematicsDeterminants
The value of | array lll x & p & q p & x & q p & q & x array | is
Options
- A(x-p)(x-q)(x+p+q)
- Bx(x-p)(x-q)
- Cp q(x-p)(x-q)
- D(p-q)(x-q)(x-p)
Correct answer
A. (x-p)(x-q)(x+p+q)
Step-by-step solution
We have [ array lll x & p & q p & x & q p & q & x array ] Applying C₁ C₁+C₂+C₃₃ , we get | array lll x+p+q & p & q x+p+q & x & q x+p+q & q & x array | Taking common (x+p+q) from C₁ , we get (x+p+q) | array lll 1 & p & q 1 & x & q 1 & q & k array | Applying R₁ R₁-R₂, R₂ R₂-R₃ , we get aligned &(x+p+q) | array ccc 0 & p-x & 0 0 & x-q & q-x 1 & q & x array | &=(x+p+q) 1[(p-x)(q-x)-0] &= (x-p)(x-q)(x+p+q) aligned