Program Equa_2d;
Var a, b, c, delta : Real;
Begin
Writeln('a = ');
Readln (a);
Writeln('b = ');
Readln (b);
Write ('c = ');
Readln (c);
{équation 1er degré}
If a = 0 Then If b = 0 Then If c = 0 Then Writeln ('IR')
Else Writeln ('{}') Else Writeln ('x = ', -c/b)
Else delta := sqr (b) - 4*a*c;
{solution réelle double}
If delta = 0 Then Writeln ('x1=x2= ', -b/ (2*a))
{deux solutions réelles}
Else If delta > 0  Then
Begin
Writeln ('x1= ', (-b-sqrt (delta))/ (2*a):2:2);
Writeln ('x2= ', (-b+sqrt (delta))/ (2*a):2:2);
End
Else Writeln ('Deux solutions complexes');
End.