If you have an augmented matrix and one column in your matrix is all zero (but not the answer column) are you able to 'delete' the all zero column and the corresponding variable? Because when you write out the equations, the co-efficient's of the variable corresponding to the all zero column are of course, all zero. Doesn't this mean that that variable is not important in these equations, and that no other variables are dependent upon this variable. And on another note, can it even be considered a variable since nothing is dependent on this 'variable' and it can take any value without affecting it at all. Thank you!