NTA Abhyas JEE Main2020MathematicsDeterminantsPractice
The system of equations α x - 1 + y + z = - 1 , x + α y - 1 + z = - 1 and x + y + α z - 1 = - 1 has no solution, if α is equal to
Options
- A- 2 o r 1
- B- 2
- C1
- D- 1
Correct answer
B. - 2
Step-by-step solution
Rearranging the given equations, we get, α x + y + z = α - 1 x + α y + z = α - 1 x + y + α z = α - 1 For no solution, Δ = 0 and atleast one of Δ 1 , Δ 2 , Δ 3 must be non zero. Δ = α 1 1 1 α 1 1 1 α = α α 2 - 1 - 1 α - 1 + 1 1 - α = α - 1 α 2 + α - 1 - 1 = 0 ⇒ α + 2 α - 1 2 = 0 ⇒ α = - 2 , 1 Δ 1 = α - 1 1 1 α - 1 α 1 α - 1 1 α = α - 1 α 2 - 1 - 1