>> 
>> 
>> A1 = [-2,-2,2,2,-2;1,-5,1,-3,-1;-1,2,-5,6,5;-1,2,1,0,-1]

A1 =

    -2    -2     2     2    -2
     1    -5     1    -3    -1
    -1     2    -5     6     5
    -1     2     1     0    -1

>> 
>> b = [-2;-1;2;0]

b =

    -2
    -1
     2
     0

>> 
>> 
>> 
>> rref([A1,b])

ans =

    1.0000         0         0         0         0   -0.2222
         0    1.0000         0         0         0    0.2222
         0         0    1.0000         0   -1.0000   -0.6667
         0         0         0    1.0000         0   -0.3333

>> 
>>