[Maxima] Simplification question

[Andreas Kranz]

Hello,

as a maxima newbie I've trouble understanding how to achieve a certain 
transformation.

Especially I would like the following term:

  2 vx z - r z - l z - 2 n (x - vx) - 2 vz x + r vz + l vz
- --------------------------------------------------------
                           r - l

to be written as:


2(n + vz)      -2 vx    r + l       2 n vx + r vz + l vz
--------- x + (----- +  -----) z +  --------------------
  r - l        r - l    r - l              r - l


probably an easy task for maxima but maybe I'm just to blind to see how 
to do this.
I've already experimented with combinations of factorsum, factorout and 
friends but
could not work that out.

Any suggestions?

Bye,

Andreas