#Example: S({x+y-3,x-y+11},{x,y}); is the solution of the system of two equations (in the  two unknowns {x,y}), x+y=3, x-y=-11
S:=proc(eq,var) local i,eq1,eqN,varN,gu,x,xN,SN:

if eq={} then
 RETURN({seq(var[i]=var[i],i=1..nops(var))}):
fi:

eq1:=eq[1]:

print(`eq1 is`):
for i from 1 to nops(var) while coeff(eq1,var[i],1)=0 do od:

 if i=nops(var)+1 then
   RETURN({}):
 fi:

x:=var[i]:

print(` x is `, x):

gu:=-coeff(eq1,x,0)/coeff(eq1,x,1):
varN:=var minus {x}:
eqN:=eq minus {eq1}:
eqN:=subs(x=gu,eqN):

SN:=S(eqN,varN):
xN:=subs(SN,gu):
SN union {x=xN}:
end: