>> A = [1 -3 2; -2 4 1]   **** input A 
A =
     1    -3     2
    -2     4     1
>> B = [0 1; -3 4; -1 2], C = rand(3,3)
B =
     0     1
    -3     4
    -1     2
C =
    0.9501    0.4860    0.4565
    0.2311    0.8913    0.0185
    0.6068    0.7621    0.8214
>> bb = [1;2]        ***  will solve A*x = bb
bb =
     1
     2
>> A(:,1)      **** pick the first column of A
ans =
     1
    -2
>> A*B, B*A     ****  A*B may not equal B*A
ans =
     7    -7
   -13    16
ans =
    -2     4     1
   -11    25    -2
    -5    11     0
>> eye(3)           **** generate identity matrix
ans =
     1     0     0
     0     1     0
     0     0     1
>> inv(C)
ans =
    1.6740   -0.1196   -0.9276
   -0.4165    1.1738    0.2050
   -0.8504   -1.0006    1.7125
>> inv(C)*C
ans =
    1.0000    0.0000         0
    0.0000    1.0000         0
         0   -0.0000    1.0000
>> rref(A)
ans =
    1.0000         0   -5.5000
         0    1.0000   -2.5000
>> x = A\bb
x =
         0
    0.2727
    0.9091
>> rref([A bb])
ans =
    1.0000         0   -5.5000   -5.0000
         0    1.0000   -2.5000   -2.0000