Const
 e=0.00001;

Var
 x,dx:real;

Function F(z:real):Real;
begin
 F:=z*z*z-z*2-13;
end;

Begin
 x:=10;
 dx:=1;
 Repeat
  repeat
   x:=x-dx;
  until F(x)<0;
  x:=x+dx;
  dx:=dx/10;
 Until dx<e;
 Writeln('x= ',x:0:5,'    F(x)= ',F(x):0:8);
 Readln
End.