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If P=[(1,alpha,3),(1,3,3),(2,4,4)] is th...

If `P=[(1,alpha,3),(1,3,3),(2,4,4)]` is the adjoint of a `3xx3` matrix A and det. `(A)=4`, then the value of alpha is ______ .

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Verified by Experts

The correct Answer is:
11

A= adj. B
`implies |A|=|"adj. B"|=|B|^(2)`
`:. |A|=(4)^(2) implies |A|=16`
`implies |(1,x,3),(1,3,3),(2,4,4)|=16`
`implies 1(0)-x(-2)+3(-2)=16`
`implies 2x=22`
`implies x=11`
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