         
         if aDivisor == bDivisor
         {
-            let newDividend:Double = aDividend - bDividend
+            let newDividend:Double
+            
+            if inverse
+            {
+                newDividend = aDividend - bDividend
+            }
+            else
+            {
+                newDividend = aDividend + bDividend
+            }
+            
             polynomialA.coefficientDividend = abs(newDividend)
             
             if newDividend < 0

        }
    }
    
    private func merge(polynomialA:DPolynomial, polynomialB:DPolynomial)
    {
        let aSign:Double
        let bSign:Double

        {
            merge(
                polynomialA:polynomial,
                polynomialB:result,
                inverse:true)
            
            DManager.sharedInstance?.createManagedObject(
                entityName:DPolynomial.entityName)
