             guard
             
                 let polynomials:[DPolynomial] = equation.polynomials?.array as? [DPolynomial],
-                var result:DPolynomial? = equation.result
+                let result:DPolynomial = equation.result
             
             else
             {

        {
            merge(
                polynomialA:polynomial,
                polynomialB:compare)
            
            equation.removeFromPolynomials(compare)
            DManager.sharedInstance?.delete(object:compare)

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