Answer :
The result of operation A - 1 is:
0 0 -3
-10 -2 -1
-3 -2 1
which is equal to matrix B.
Looking at the third row we have:
b31 = -3
b32 = -2
b33 = 1
which are the entries in the third row of A - 1
0 0 -3
-10 -2 -1
-3 -2 1
which is equal to matrix B.
Looking at the third row we have:
b31 = -3
b32 = -2
b33 = 1
which are the entries in the third row of A - 1