Solve a simultaneous equation, where the left hand side depends, directly or indirectly, on the right hand side, without any intervening levels. simeqn is the equation to be solved iteratively. initval is the initial solution; normally this is not known but should be at least a plausible guess.
|Units:||SIMULTANEOUS(units,units) --> units|
See the example in Iterative Solutions to Active Simultaneous Equations