Logged In: YES

user_id=895922

Originator: NO

With algebraic : true, we get a different error:

(%i7) solve(sys, [a1, a2, a3, a5, r2, r3, r4, b1, b2]), algebraic : true;

`algsys' cannot solve - system too complicated. -- an error. To debug this try debugmode(true);