(%i1) (x-sqrt(3))*(x+sqrt(3)); (%o1) (x-sqrt(3))*(x+sqrt(3)) (%i2) expand(%); (%o2) x^2-3 On Thu, Apr 2, 2009 at 7:18 PM, Gosse michel <michel.gosse at ac-lille.fr>wrote: > (x-sqrt(3))*(x+sqrt(3)) >