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Let A be a non-singular square matrix such that A2=A satisfying Ι-0.8A-1=Ι-αA where Ι is a unit matrix of the same order as that of A, then the value of -4α is equal to
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Solution:
2207 Upvotes Verified Answer
The correct answer is: 16
Ι-0.8A-1=Ι-αA

Ι-0.8AΙ-0.8A-1=Ι-0.8AΙ-αA

Ι=Ι-α+45A+4α5A2

Aα+45=4α5Aα5=-45α=-4

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