M=
  -0.5502    0.5154    0.4739 
    1.368   -0.9168   -0.1241 
   -2.011   -0.4928    0.3926 
qrm.A=
    2.494   -0.2194   -0.4892 
    1.953     1.141   0.05019 
   -0.938     -1.69   -0.3901 
b=
  -0.9292   0.07983   -0.1595 
x=
   -0.268   -0.2104    -2.043 
M*x=
  -0.9292   0.07983   -0.1595 
M*x-b
1.849e-16 4.555e-17 -8.674e-17 
M*x==b ? : 1
MI=
   0.3795    0.3928   -0.3338 
   0.2591    -0.664   -0.5228 
    2.269     1.178     0.181 
MI*M=
        1 3.334e-18 2.575e-18 
-1.677e-16         1 2.631e-17 
-2.73e-16 -2.078e-17         1 
M*MI=
        1 -6.614e-18 1.235e-16 
6.329e-17         1 -1.464e-16 
-3.15e-17 -7.186e-17         1 


M=
-0.550234 0.515433 0.473861 
1.36845 -0.916827 -0.124147 
-2.01096 -0.492803 0.39258 
qrm.A=
2.49387 -0.219431 -0.489235 
1.9531 1.14059 0.0501909 
-0.937976 -1.69049 -0.390136 
b= -0.929185 0.0798318 -0.159516 
x= -0.267989 -0.210403 -2.0432 
M*x= -0.929185 0.0798318 -0.159516 
M*x-b -1.40946e-17 2.85755e-17 -2.35814e-18 
M*x==b ? : 1
MI=
0.379467 0.392768 -0.333826 
0.259134 -0.664037 -0.522778 
2.26908 1.17837 0.181011 
MI*M=
1 -4.79082e-17 -2.99104e-17 
1.29128e-16 1 8.5923e-18 
3.77546e-16 -1.08264e-16 1 
M*MI=
1 1.60082e-16 2.45843e-17 
-3.52095e-17 1 -1.12488e-16 
4.25549e-17 -1.6095e-16 1