/* Solution to the  Wheatstone bridge  problem  with MAXIMA */

/* Define linear system  which describes the Wheatstone bridge */
eqns:[-i1 + ix + iE = 0,
       i1 - i0 - i2 = 0,
      -iE + i2 - i3 = 0,
       i0 - ix + i3 = 0,
      -i1*R1  - i2*R2         = -E,
       i1*R1  + i0*R0 + ix*Rx =  0, 
       i2*R2  + i3*R3 - i0*R0 =  0
];

/* List variables to solve for */
vars : [i0,i1,ix,i2,i3,iE];

/* Solve the system */
soln : linsolve(eqns,vars),factor;

/* Extract i0 */
I:i0,soln,factor;

/* METHOD II */

/* Extract the augmented coefficient matrix from the system */
A:augcoefmatrix(eqns,vars);

/* Find reduced row echelon form */
U:echelon(A),factor;