Find inverse, by elementary row operations (if possible), of the following matrix.
[1−3−26]
Let A=[1−3−26]
In order to use elementary row operations, we write A = IA
⇒[1−3−26]=[1001]A
⇒[1−300]=[1021]A [∵R2→R2+2R1]
Since we obtain all zeroes in a row of the matrix A on LHS, so A−1 does not exist.