confused

-->x= [ 2 ; -2]
x =

2.
- 2.

-->b - A*x
ans =

1.0D-15 *

0.0277556
0.1110223

-->A*x
ans =

0.144
0.8642

-->b
b =

0.144
0.8642

-->A*x - b
ans =

1.0D-15 *

- 0.0277556
- 0.1110223