Trying to solve this simple equations :
solve([2 = (1-z)/x,x=0],[x,z]);
Maxima gives this result :
[[z = 1, x = 0 ]]
Which is a wrong result!
Since we multiply by x (x=0) the first equation which is a wrong algorithm.
This bug is in the 5.23.2 release (Scientific Linux) as well in the 5.24.0 (Ubuntu 12).