diff --git a/apps/regression/model/cubic_model.cpp b/apps/regression/model/cubic_model.cpp
index 32bd4d4af..1c5899e81 100644
--- a/apps/regression/model/cubic_model.cpp
+++ b/apps/regression/model/cubic_model.cpp
@@ -48,33 +48,6 @@ Layout CubicModel::layout() {
   return m_layout;
 }
 
-Expression CubicModel::simplifiedExpression(double * modelCoefficients, Poincare::Context * context) {
-  double a = modelCoefficients[0];
-  double b = modelCoefficients[1];
-  double c = modelCoefficients[2];
-  double d = modelCoefficients[3];
-  Expression addChildren[] = {
-    Multiplication::Builder(
-      Number::DecimalNumber(a),
-      Power::Builder(
-        Symbol::Builder('x'),
-        Decimal::Builder(3.0))),
-    Multiplication::Builder(
-      Number::DecimalNumber(b),
-      Power::Builder(
-        Symbol::Builder('x'),
-        Decimal::Builder(2.0))),
-    Multiplication::Builder(
-      Number::DecimalNumber(c),
-      Symbol::Builder('x')),
-    Number::DecimalNumber(d)
-    };
-  // a*x^3+b*x^2+c*x+d
-  Expression result = Addition::Builder(addChildren, 4);
-  PoincareHelpers::Simplify(&result, *context);
-  return result;
-}
-
 double CubicModel::evaluate(double * modelCoefficients, double x) const {
   double a = modelCoefficients[0];
   double b = modelCoefficients[1];
@@ -104,4 +77,30 @@ double CubicModel::partialDerivate(double * modelCoefficients, int derivateCoeff
   return 0.0;
 }
 
+Expression CubicModel::expression(double * modelCoefficients) {
+  double a = modelCoefficients[0];
+  double b = modelCoefficients[1];
+  double c = modelCoefficients[2];
+  double d = modelCoefficients[3];
+  Expression addChildren[] = {
+    Multiplication::Builder(
+      Number::DecimalNumber(a),
+      Power::Builder(
+        Symbol::Builder('x'),
+        Decimal::Builder(3.0))),
+    Multiplication::Builder(
+      Number::DecimalNumber(b),
+      Power::Builder(
+        Symbol::Builder('x'),
+        Decimal::Builder(2.0))),
+    Multiplication::Builder(
+      Number::DecimalNumber(c),
+      Symbol::Builder('x')),
+    Number::DecimalNumber(d)
+    };
+  // a*x^3+b*x^2+c*x+d
+  Expression result = Addition::Builder(addChildren, 4);
+  return result;
+}
+
 }
diff --git a/apps/regression/model/cubic_model.h b/apps/regression/model/cubic_model.h
index 833f26060..1e8918e4c 100644
--- a/apps/regression/model/cubic_model.h
+++ b/apps/regression/model/cubic_model.h
@@ -9,12 +9,13 @@ class CubicModel : public Model {
 public:
   using Model::Model;
   Poincare::Layout layout() override;
-  Poincare::Expression simplifiedExpression(double * modelCoefficients, Poincare::Context * context) override;
   I18n::Message formulaMessage() const override { return I18n::Message::CubicRegressionFormula; }
   double evaluate(double * modelCoefficients, double x) const override;
   double partialDerivate(double * modelCoefficients, int derivateCoefficientIndex, double x) const override;
   int numberOfCoefficients() const override { return 4; }
   int bannerLinesCount() const override { return 4; }
+private:
+  Poincare::Expression expression(double * modelCoefficients) override;
 };
 
 }
diff --git a/apps/regression/model/model.cpp b/apps/regression/model/model.cpp
index eb90bb77e..78e7891dd 100644
--- a/apps/regression/model/model.cpp
+++ b/apps/regression/model/model.cpp
@@ -15,6 +15,14 @@ void Model::tidy() {
   m_layout = Layout();
 }
 
+Poincare::Expression Model::simplifiedExpression(double * modelCoefficients, Poincare::Context * context) {
+  Expression e = expression(modelCoefficients);
+  if (!e.isUninitialized()) {
+    PoincareHelpers::Simplify(&e, *context);
+  }
+  return e;
+}
+
 double Model::levelSet(double * modelCoefficients, double xMin, double step, double xMax, double y, Poincare::Context * context) {
   Expression yExpression = Number::DecimalNumber(y);
   PoincareHelpers::Simplify(&yExpression, *context);
diff --git a/apps/regression/model/model.h b/apps/regression/model/model.h
index 2a233fe84..b45247961 100644
--- a/apps/regression/model/model.h
+++ b/apps/regression/model/model.h
@@ -30,8 +30,7 @@ public:
   virtual Poincare::Layout layout() = 0;
   // Reinitialize m_layout to empty the pool
   void tidy();
-  // simplifiedExpression is overrided only by Models that override levelSet
-  virtual Poincare::Expression simplifiedExpression(double * modelCoefficients, Poincare::Context * context) { return Poincare::Expression(); }
+  Poincare::Expression simplifiedExpression(double * modelCoefficients, Poincare::Context * context);
   virtual I18n::Message formulaMessage() const = 0;
   virtual double evaluate(double * modelCoefficients, double x) const = 0;
   virtual double levelSet(double * modelCoefficients, double xMin, double step, double xMax, double y, Poincare::Context * context);
@@ -45,6 +44,7 @@ protected:
   Poincare::Layout m_layout;
 private:
   // Model attributes
+  virtual Poincare::Expression expression(double * modelCoefficients) { return Poincare::Expression(); } // expression is overrided only by Models that do not override levelSet
   virtual double partialDerivate(double * modelCoefficients, int derivateCoefficientIndex, double x) const = 0;
 
   // Levenberg-Marquardt
diff --git a/apps/regression/model/quadratic_model.cpp b/apps/regression/model/quadratic_model.cpp
index a2cb20400..67305337f 100644
--- a/apps/regression/model/quadratic_model.cpp
+++ b/apps/regression/model/quadratic_model.cpp
@@ -40,27 +40,6 @@ Layout QuadraticModel::layout() {
   return m_layout;
 }
 
-Expression QuadraticModel::simplifiedExpression(double * modelCoefficients, Poincare::Context * context) {
-  double a = modelCoefficients[0];
-  double b = modelCoefficients[1];
-  double c = modelCoefficients[2];
-  // a*x^2+b*x+c
-  Expression addChildren[] = {
-    Multiplication::Builder(
-      Number::DecimalNumber(a),
-      Power::Builder(
-        Symbol::Builder('x'),
-        Decimal::Builder(2.0))),
-    Multiplication::Builder(
-      Number::DecimalNumber(b),
-      Symbol::Builder('x')),
-    Number::DecimalNumber(c)
-  };
-  Expression result = Addition::Builder(addChildren, 3);
-  PoincareHelpers::Simplify(&result, *context);
-  return result;
-}
-
 double QuadraticModel::evaluate(double * modelCoefficients, double x) const {
   double a = modelCoefficients[0];
   double b = modelCoefficients[1];
@@ -85,4 +64,24 @@ double QuadraticModel::partialDerivate(double * modelCoefficients, int derivateC
   return 0.0;
 }
 
+Expression QuadraticModel::expression(double * modelCoefficients) {
+  double a = modelCoefficients[0];
+  double b = modelCoefficients[1];
+  double c = modelCoefficients[2];
+  // a*x^2+b*x+c
+  Expression addChildren[] = {
+    Multiplication::Builder(
+      Number::DecimalNumber(a),
+      Power::Builder(
+        Symbol::Builder('x'),
+        Decimal::Builder(2.0))),
+    Multiplication::Builder(
+      Number::DecimalNumber(b),
+      Symbol::Builder('x')),
+    Number::DecimalNumber(c)
+  };
+  Expression result = Addition::Builder(addChildren, 3);
+  return result;
+}
+
 }
diff --git a/apps/regression/model/quadratic_model.h b/apps/regression/model/quadratic_model.h
index c56894498..01357f9ce 100644
--- a/apps/regression/model/quadratic_model.h
+++ b/apps/regression/model/quadratic_model.h
@@ -9,12 +9,13 @@ class QuadraticModel : public Model {
 public:
   using Model::Model;
   Poincare::Layout layout() override;
-  Poincare::Expression simplifiedExpression(double * modelCoefficients, Poincare::Context * context) override;
   I18n::Message formulaMessage() const override { return I18n::Message::QuadraticRegressionFormula; }
   double evaluate(double * modelCoefficients, double x) const override;
   double partialDerivate(double * modelCoefficients, int derivateCoefficientIndex, double x) const override;
   int numberOfCoefficients() const override { return 3; }
   int bannerLinesCount() const override { return 3; }
+private:
+  Poincare::Expression expression(double * modelCoefficients) override;
 };
 
 }
diff --git a/apps/regression/model/quartic_model.cpp b/apps/regression/model/quartic_model.cpp
index 09388c0a3..32a2323a8 100644
--- a/apps/regression/model/quartic_model.cpp
+++ b/apps/regression/model/quartic_model.cpp
@@ -56,43 +56,6 @@ Layout QuarticModel::layout() {
   return m_layout;
 }
 
-Expression QuarticModel::simplifiedExpression(double * modelCoefficients, Poincare::Context * context) {
-  double a = modelCoefficients[0];
-  double b = modelCoefficients[1];
-  double c = modelCoefficients[2];
-  double d = modelCoefficients[3];
-  double e = modelCoefficients[4];
-  Expression addChildren[] = {
-    // a*x^4
-    Multiplication::Builder(
-      Number::DecimalNumber(a),
-      Power::Builder(
-        Symbol::Builder('x'),
-        Decimal::Builder(4.0))),
-    // b*x^3
-    Multiplication::Builder(
-      Number::DecimalNumber(b),
-      Power::Builder(
-        Symbol::Builder('x'),
-        Decimal::Builder(3.0))),
-    // c*x^2
-    Multiplication::Builder(
-      Number::DecimalNumber(c),
-      Power::Builder(
-        Symbol::Builder('x'),
-        Decimal::Builder(2.0))),
-    // d*x
-    Multiplication::Builder(
-      Number::DecimalNumber(d),
-      Symbol::Builder('x')),
-    // e
-    Number::DecimalNumber(e)
-  };
-  Expression result = Addition::Builder(addChildren, 5);
-  PoincareHelpers::Simplify(&result, *context);
-  return result;
-}
-
 double QuarticModel::evaluate(double * modelCoefficients, double x) const {
   double a = modelCoefficients[0];
   double b = modelCoefficients[1];
@@ -127,4 +90,40 @@ double QuarticModel::partialDerivate(double * modelCoefficients, int derivateCoe
   return 0.0;
 }
 
+Expression QuarticModel::expression(double * modelCoefficients) {
+  double a = modelCoefficients[0];
+  double b = modelCoefficients[1];
+  double c = modelCoefficients[2];
+  double d = modelCoefficients[3];
+  double e = modelCoefficients[4];
+  Expression addChildren[] = {
+    // a*x^4
+    Multiplication::Builder(
+      Number::DecimalNumber(a),
+      Power::Builder(
+        Symbol::Builder('x'),
+        Decimal::Builder(4.0))),
+    // b*x^3
+    Multiplication::Builder(
+      Number::DecimalNumber(b),
+      Power::Builder(
+        Symbol::Builder('x'),
+        Decimal::Builder(3.0))),
+    // c*x^2
+    Multiplication::Builder(
+      Number::DecimalNumber(c),
+      Power::Builder(
+        Symbol::Builder('x'),
+        Decimal::Builder(2.0))),
+    // d*x
+    Multiplication::Builder(
+      Number::DecimalNumber(d),
+      Symbol::Builder('x')),
+    // e
+    Number::DecimalNumber(e)
+  };
+  Expression result = Addition::Builder(addChildren, 5);
+  return result;
+}
+
 }
diff --git a/apps/regression/model/quartic_model.h b/apps/regression/model/quartic_model.h
index a5aadd965..61657428d 100644
--- a/apps/regression/model/quartic_model.h
+++ b/apps/regression/model/quartic_model.h
@@ -9,12 +9,13 @@ class QuarticModel : public Model {
 public:
   using Model::Model;
   Poincare::Layout layout() override;
-  Poincare::Expression simplifiedExpression(double * modelCoefficients, Poincare::Context * context) override;
   I18n::Message formulaMessage() const override { return I18n::Message::QuarticRegressionFormula; }
   double evaluate(double * modelCoefficients, double x) const override;
   double partialDerivate(double * modelCoefficients, int derivateCoefficientIndex, double x) const override;
   int numberOfCoefficients() const override { return 5; }
   int bannerLinesCount() const override { return 4; }
+private:
+  Poincare::Expression expression(double * modelCoefficients) override;
 };
 
 }
diff --git a/apps/regression/model/trigonometric_model.cpp b/apps/regression/model/trigonometric_model.cpp
index d090ede6b..2475f61e0 100644
--- a/apps/regression/model/trigonometric_model.cpp
+++ b/apps/regression/model/trigonometric_model.cpp
@@ -24,27 +24,6 @@ Layout TrigonometricModel::layout() {
   return m_layout;
 }
 
-Expression TrigonometricModel::simplifiedExpression(double * modelCoefficients, Poincare::Context * context) {
-  double a = modelCoefficients[0];
-  double b = modelCoefficients[1];
-  double c = modelCoefficients[2];
-  double d = modelCoefficients[3];
-  // a*sin(bx+c)+d
-  Expression result =
-    Addition::Builder(
-      Multiplication::Builder(
-        Number::DecimalNumber(a),
-        Sine::Builder(
-          Addition::Builder(
-            Multiplication::Builder(
-              Number::DecimalNumber(b),
-              Symbol::Builder('x')),
-            Number::DecimalNumber(c)))),
-      Number::DecimalNumber(d));
-  PoincareHelpers::Simplify(&result, *context);
-  return result;
-}
-
 double TrigonometricModel::evaluate(double * modelCoefficients, double x) const {
   double a = modelCoefficients[0];
   double b = modelCoefficients[1];
@@ -79,4 +58,24 @@ double TrigonometricModel::partialDerivate(double * modelCoefficients, int deriv
   return 0.0;
 }
 
+Expression TrigonometricModel::expression(double * modelCoefficients) {
+  double a = modelCoefficients[0];
+  double b = modelCoefficients[1];
+  double c = modelCoefficients[2];
+  double d = modelCoefficients[3];
+  // a*sin(bx+c)+d
+  Expression result =
+    Addition::Builder(
+      Multiplication::Builder(
+        Number::DecimalNumber(a),
+        Sine::Builder(
+          Addition::Builder(
+            Multiplication::Builder(
+              Number::DecimalNumber(b),
+              Symbol::Builder('x')),
+            Number::DecimalNumber(c)))),
+      Number::DecimalNumber(d));
+  return result;
+}
+
 }
diff --git a/apps/regression/model/trigonometric_model.h b/apps/regression/model/trigonometric_model.h
index b328286f5..a22bf69a0 100644
--- a/apps/regression/model/trigonometric_model.h
+++ b/apps/regression/model/trigonometric_model.h
@@ -9,15 +9,15 @@ class TrigonometricModel : public Model {
 public:
   using Model::Model;
   Poincare::Layout layout() override;
-  Poincare::Expression simplifiedExpression(double * modelCoefficients, Poincare::Context * context) override;
   I18n::Message formulaMessage() const override { return I18n::Message::TrigonometricRegressionFormula; }
   double evaluate(double * modelCoefficients, double x) const override;
   double partialDerivate(double * modelCoefficients, int derivateCoefficientIndex, double x) const override;
   int numberOfCoefficients() const override { return 4; }
   int bannerLinesCount() const override { return 4; }
+private:
+  Poincare::Expression expression(double * modelCoefficients) override;
 };
 
 }
 
-
 #endif