diff --git a/TODO b/TODO
index 64b0f4a..db39e93 100644
--- a/TODO
+++ b/TODO
@@ -5,7 +5,7 @@
 * bug: expression can't handle -(-2)
 * Overload + - * for expression (DONE ~ no steps yet)
 * Expression should be able to simplify expression with ":"
+* Add name to polynom
 
 * Expression parents class and his children: Numerical_exp, toGenerate_exp and formal expression
 * Create tbl sgn and variation render
-* Give a name to polynoms
diff --git a/bugs b/bugs
index 5d1f54b..553d1d1 100644
--- a/bugs
+++ b/bugs
@@ -1,3 +1,7 @@
+* Soustraction de Polynômes!!!!
+
+
+
 * Expression importe mal 4x^2
     In [9]: e = Expression("3x + 4x^2 - 1")
 
diff --git a/pymath/polynom.py b/pymath/polynom.py
index 13a17b6..2bef1eb 100644
--- a/pymath/polynom.py
+++ b/pymath/polynom.py
@@ -64,9 +64,9 @@ class Polynom(Explicable):
         # On "parse" ce string pour créer les coefs
         coefs = [eval(i) if type(i)==str else i for i in eval(coefs)]
         # Création du polynom
-        return Polynom(coef = coefs, letter = letter, name = name)
+        return Polynom(coefs = coefs, letter = letter, name = name)
 
-    def __init__(self, coef = [1], letter = "x", name = "P"):
+    def __init__(self, coefs = [1], letter = "x", name = "P"):
         """Initiate the polynom
 
         :param coef: coefficients of the polynom (ascending degree sorted)
@@ -96,7 +96,7 @@ class Polynom(Explicable):
         'Q'
         """
         super(Polynom, self).__init__()
-        self.feed_coef(coef)
+        self.feed_coef(coefs)
         self._letter = letter
         self.name = name
 
diff --git a/pymath/polynomDeg2.py b/pymath/polynomDeg2.py
index 099eff2..9a87efb 100644
--- a/pymath/polynomDeg2.py
+++ b/pymath/polynomDeg2.py
@@ -4,8 +4,10 @@
 from .polynom import Polynom
 from .expression import Expression
 from .operator import op
+from .random_expression import RdExpression
 from math import sqrt
 
+__all__ = ["Polynom_deg2"]
 
 class Polynom_deg2(Polynom):
 
@@ -13,6 +15,26 @@ class Polynom_deg2(Polynom):
     Child of Polynom with some extra tools
     """
 
+    @classmethod
+    def random(self, coefs_form = ["{c}", "{b}", "{a}"], conditions = [], letter = "x", name = "P"):
+        """ Create a 2nd degree poly from coefs_form ans conditions
+
+        :param coefs_form: list of forms (one by coef) (ascending degree sorted)
+        :param conditions: condition on variables 
+        :param letter: the letter for the polynom
+
+        """
+        if len(coefs_form) != 3:
+            raise ValueError("Polynom_deg2 have to be degree 2 polynoms, they need 3 coefficients, {} are given".format(len(coefs_form)))
+
+        form = str(coefs_form)
+        # On créé les valeurs toutes concaténées dans un string
+        coefs = RdExpression(form, conditions)()
+        # On "parse" ce string pour créer les coefs
+        coefs = [eval(i) if type(i)==str else i for i in eval(coefs)]
+        # Création du polynom
+        return Polynom_deg2(coefs = coefs, letter = letter, name = name)
+
     def __init__(self, coefs = [0, 0, 1], letter = "x", name = "P"):
         if len(coefs) < 3 or len(coefs) > 4:
             raise ValueError("Polynom_deg2 have to be degree 2 polynoms, they need 3 coefficients, {} are given".format(len(coefs)))
@@ -83,7 +105,7 @@ class Polynom_deg2(Polynom):
         """
         return self(self.alpha).simplify()
 
-    def roots(self):
+    def roots(self, after_coma = 2):
         """ Compute roots of the polynom
 
         /!\ Can't manage exact solution because of pymath does not handle sqare root yet
@@ -101,12 +123,21 @@ class Polynom_deg2(Polynom):
         [-1.0, 1.0]
         """
         if self.delta > 0:
-            self.roots = [(-self.b - sqrt(self.delta))/(2*self.a), (-self.b + sqrt(self.delta))/(2*self.a)]
+            self._roots = [round((-self.b - sqrt(self.delta))/(2*self.a),after_coma), round((-self.b + sqrt(self.delta))/(2*self.a),after_coma)]
         elif self.delta == 0:
-            self.roots = [-self.b /(2*self.a)]
+            self._roots = [round(-self.b /(2*self.a), after_coma)]
         else:
-            self.roots = []
-        return self.roots
+            self._roots = []
+        return self._roots
+
+    def tbl_sgn_header(self):
+        """ Return header of the sign line for tkzTabLine"""
+        if self.delta > 0:
+            return  "{$-\\infty$, " + str(min(self.roots())) + " , " + str( max(self.roots())) + " , $+\\infty$}"
+        elif self.delta == 0:
+            return  "{$-\\infty$, " +  str(self.roots()[0])  + " , $+\\infty$}"
+        else:
+            return  "{$-\\infty$, $+\\infty$}"
 
     def tbl_sgn(self):
         """ Return the sign line for tkzTabLine