Q26 / 75 · JEE Main 2020 (03 Sep Shift 2) · Mathematics

Let A be a 3×3 matrix such that adjA=2-11-1021-2-1 and B=adjadjA. If |A|=λ and B-1⊤=μ, then the ordered pair λ, μ is equal to

  • Correct answer
    A
    3, 181
  • B
    9, 19
  • C
    3, 81
  • D
    9, 181

Solution

adj A=A2=9

⇒A=±3=λ⇒λ=3

⇒B=adj A2=81

⇒B-1T=B-1=B-1=1B=181=μ

∴λ, μ=3, 181.

Hence, the correct answer is option: 'A'.

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