diff --git a/pymath/polynomDeg2.py b/pymath/polynomDeg2.py
index 1f76e1d..ac223be 100644
--- a/pymath/polynomDeg2.py
+++ b/pymath/polynomDeg2.py
@@ -156,9 +156,9 @@ class Polynom_deg2(Polynom):
     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())) + " , $+\\infty$}"
+            return  "{$-\\infty$, $" + str(min(self.roots())) + "$ , $" + str( max(self.roots())) + "$ , $+\\infty$}"
         elif self.delta == 0:
-            return  "{$-\\infty$, " +  str(self.roots()[0])  + " , $+\\infty$}"
+            return  "{$-\\infty$, $" +  str(self.roots()[0])  + "$ , $+\\infty$}"
         else:
             return  "{$-\\infty$, $+\\infty$}"