I had to change my strategy, but am faced again with a hard (for Derive)   
   to solve system of 9 polynomial equations (= 0 implied):   
      
   [x3*x5 + x6*x7 + x8^2 - x9, x1*x5 + x4*x7 + x7*x8 + 1, x0*x5 + x2*x7 +   
   x5*x8, x2*x3 + x4*x6 + x6*x8 - x9, x1*x2 + x4^2 + x6*x7 - x9 + 1, x0*x2   
   + x2*x4 + x5*x6 + 2, x0*x3 + x1*x6 + x3*x8, x0*x1 + x1*x4 + x3*x7 - x9,   
   x0^2 + x1*x2 + x3*x5 - x9 + 2]   
      
   I am interested in bivariate polynomials containing only [x8, x9], but   
   am having difficulties eliminating the variables [x0, x1, x2, x3, x4,   
   x5, x6, x7] from this system.   
      
   A corresponding Mathematica command may be something like   
      
   GroebnerBasis[{...}, {x8, x9}, {x0, x1, x2, x3, x4, x5, x6, x7},   
     MonomialOrder -> EliminationOrder] // First // Factor   
      
   where "..." represents the above system (without the surrounding   
   brackets). The "First" would throw away all but the first basis element,   
   and the "Factor" is hoped to reveal simple factors.   
      
   Martin.   
      
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