Fix quadratic formula for the roots

docs/csharp/expression-classes.md

@@ -16,7 +16,7 @@ Rather than run through the full list, let's understand how the framework classe
 
 In language design, an expression is a body of code that evaluates and returns a value. Expressions
 may be very simple: the constant expression `1` returns the constant value of 1. They may be more
-complicated: The expression `(-B + Math.Sqrt(B*B + 4 * A * C)) / (2 * A)` returns one root for a
+complicated: The expression `(-B + Math.Sqrt(B*B - 4 * A * C)) / (2 * A)` returns one root for a
 quadratic equation (in the case where the equation has a solution).  
 
 ## It all starts with System.Linq.Expression

docs/csharp/programming-guide/concepts/iterators.md

@@ -212,7 +212,7 @@ public class Zoo : IEnumerable
 ```  
 
 ##  <a name="BKMK_GenericList"></a> Using Iterators with a Generic List  
- In the following example, the `Stack(Of T)` generic class implements the <xref:System.Collections.Generic.IEnumerable%601> generic interface. The `Push` method assigns values to an array of type `T`. The <xref:System.Collections.Generic.IEnumerable%601.GetEnumerator%2A> method returns the array values by using the `yield return` statement.  
+ In the following example, the <xref:System.Collections.Generic.Stack%601> generic class implements the <xref:System.Collections.Generic.IEnumerable%601> generic interface. The <xref:System.Collections.Generic.Stack%601.Push%2A> method assigns values to an array of type `T`. The <xref:System.Collections.Generic.IEnumerable%601.GetEnumerator%2A> method returns the array values by using the `yield return` statement.  
 
  In addition to the generic <xref:System.Collections.Generic.IEnumerable%601.GetEnumerator%2A> method, the non-generic <xref:System.Collections.IEnumerable.GetEnumerator%2A> method must also be implemented. This is because <xref:System.Collections.Generic.IEnumerable%601> inherits from <xref:System.Collections.IEnumerable>. The non-generic implementation defers to the generic implementation.  
 

docs/standard/microservices-architecture/implement-resilient-applications/implement-resilient-entity-framework-core-sql-connections.md

@@ -90,4 +90,4 @@ The first DbContext is \_catalogContext and the second DbContext is within the \
 
 >[!div class="step-by-step"]
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+[Next](explore-custom-http-call-retries-exponential-backoff.md)