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`[[2,3,-1,-1],[1,-1,-2,-4],[3,1,3,-2],[6,3,0,-7]]` Find rank of this matrix.

Answer» Given matrix is,
`[[2,3,-1,-1],[1,-1,-2,-4],[3,1,3,-2],[6,3,0,-7]]`
Applying `R_4=>R_4-R_1-R_2-R_3`
`=[[2,3,-1,-1],[1,-1,-2,-4],[3,1,3,-2],[0,0,0,0]]`
As complete `R_4` is `0`, so rank can not be `4`.
Now, we will take matrix,
`[[2,3,-1],[1,-1,-2],[3,1,3]]`
Determinant of the above matrix,
`D = [2(-1)-3(9)-1(4)] = -33`
As, `D !=0`, so we have a minor of `3 xx 3`.
So, rank of the given matrix is `3.`


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