Consider a matrix A = α β γ α 2 β 2 γ 2 β + γ γ + α α…

Consider a matrix A=αβγα2β2γ2β+γγ+αα+β, where α,β,γ are three distinct natural numbers.
If detadj(adjadjadjAα-β16β-γ16γ-α16=232×316, then the number of such 3- tuples α,β,γ is _______.

Solution

Given A=αβγα2β2γ2β+γγ+αα+β

R3R3+R1

A=αβγα2β2γ2α+β+γα+β+γα+β+γ

A=α+β+γαβγα2β2γ2111

A=α+β+γα-ββ-γγ-α

We know adjA=An-1

adjadjA=An-12

adjadjadjadjA=An-14

Here adjadjadjadjA=A24=A16

Given adj(adjadjadjAα-β16β-γ16γ-α16=232×316

α+β+γ16α-β16β-γ16γ-α16α-β16β-γ16γ-α16=232×316

 α+β+γ16=232·316

α+β+γ16=1216

α+β+γ=12

  α, β, γN

α-1+β-1+γ-1=9

Possible number all tuples α,β,γ will be C211=55

1 case for α=β=γ and 12 case when any two of these are equal are also included here but αβγ

Hence, number of distinct tuples α,β,γ

=55-13=42

Asked in: JEE Main 2022 (27 Jul Shift 2)

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