Q.

Consider the system of linear equations x+y+z=5,x+2y+λ2z=9,x+3y+λz=μ, where λ,μ∈R. Then which of the following statement is NOT correct                [2024]

1 System has unique solution if λ≠1 and μ≠13.  
2 System is inconsistent if λ=1 and μ≠13.  
3 System is consistent if λ≠1 and μ=13.  
4 System has infinite number of solutions if λ=1 and μ=13.  

Ans.

(1)

|11112λ213λ|=0⇒2λ2-λ-1=0

⇒λ=1,-12 and |1152λ293λμ|=0⇒μ=13

For infinite solution, λ=1 and μ=13

For unique solution λ≠1

For no solution,λ=1 and μ≠13

If λ≠1 and μ≠13

Considering the case when λ=-12 and μ≠13 this will generate no solution case.