Left matrix multiplication giving wrong answer (off by 0.125)

When I have

A= [   0.401792457631424   0.095713396253060   0.115003590060302
  -0.118005996178075  -0.395819173484325   0.252104651817522
  -0.283786461453348   0.300105777231265  -0.367108241877824];
b=[1; 0; 0];
x=A\b;

when I take

A*x

I don't get b back:

>> A*x

ans =

   1.000000000000000
   0.125000000000000
                   0

Does anyone have any ideas on what could be wrong here?

The problem persists if I use e.g. b=[1.000000000001; 0; 0], though in that case I get

>> A*x

ans =

   0.968750000000000
   0.125000000000000
   0.125000000000000

Answer 1

[Sean de Wolski]

rank(A)

 % ans = 2

shows that there are only two linearly independent rows of A, it ideally would be 3 for a 3x3 matrix.

doc rank

for more info.