Let `A =[(1,-1,1),(2,1,-3),(1,1,1)]` and `10B=[(4,2,2),(-5,0,alpha),(1,-2,3)]`. If B is the inverse of A, then `alpha` is :A. 2B. -1C. 3D. 5

Let `A =[(1,-1,1),(2,1,-3),(1,1,1)]` and `10B=[(4,2,2),(-5,0,alpha),(1

1.	Let `A =[(1,-1,1),(2,1,-3),(1,1,1)]` and `10B=[(4,2,2),(-5,0,alpha),(1,-2,3)]`. If B is the inverse of A, then `alpha` is :A. 2B. -1C. 3D. 5
Answer» Correct Answer - D It is given that B is the inverse of matrix A. `:. AB=I` `rArr A(10B)=10I` `rArr{:[(1,-1,1),(2,1,-3),(1,1,1)][(4,2,2),(-5,0,alpha),(1,-2,3)]=[(10,0,0),(0,10,0),(0,0,10)]:}` `rArr{:[(10,0,5-alpha),(0,10,alpha-5),(0,0,alpha+5)]=[(10,0,0),(0,10,0),(0,0,10)]rArralpha=5:}` ALITER : We have, `AB=I` `rArr A(10B)=10IrArr (A(10B))_13=0` `rArr{:[(1,-1,1)][(2),(alpha),(3)]=0rArr 5-alpha=0rArr a=5:}`

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Let `A =[(1,-1,1),(2,1,-3),(1,1,1)]` and `10B=[(4,2,2),(-5,0,alpha),(1,-2,3)]`. If B is the inverse of A, then `alpha` is :A. 2B. -1C. 3D. 5

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