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JEE Main202126 Feb 2021Morning ShiftMathematicsDeterminantsActual

The value of a + 1 a + 2 a + 2 1 a + 2 a + 3 a + 3 1 a + 3 a + 4 a + 4 1 is

Options

  1. A0
  2. Ba + 2 a + 3 a + 4
  3. C- 2
  4. Da + 1 a + 2 a + 3

Correct answer

C. - 2

Step-by-step solution

R 2 → R 2 - R 1 and R 3 → R 3 - R 1 Δ = a + 1 a + 2 a + 2 1 a + 2 a + 3 - a - 1 1 0 a 2 + 7 a + 12 - a 2 - 3 a - 2 2 0 = a 2 + 3 a + 2 a + 2 1 2 a + 2 1 0 4 a + 10 2 0 = 4 a + 2 - 4   a - 10 = 4 a + 8 - 4 a - 10 = - 2

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