How to calculate convert string into formula and calculate in vb

If Type = "user-defined" Then

CalculatedEqn = CSng(Evaluate(UserEquation))

Sub test()
Dim formulaString as String
Dim rangeOfValues as Variant
Dim singleValue as Variant, oneResult as Double

    formulaString = "=(Log10((delta / 324.33) ^ (1 / -0.0451)))"
    rangeOfValues = Array(0.23, 1.45, 300.4)

    For Each singleValue in rangeOfValues

        oneResult = EvaluateFormualaAt(formualString, "delta", singleValue)

        MsgBox "Formula evaluated at " & singleValue & " is " & oneResult
    Next singleValue
End Sub

Function EvaluateFormulaAt(formulaStr as String, variableName as String, evalValue as Double) As Double

    EvaluateFormulaAt = Evaluate(Replace(formulaStr, variableName, evalValue))

End Function

Sub test()
    Dim formulaString As String
    
    formulaString = "x+2*y+3"
    MsgBox EvaluateFormula(formulaString, "x", 1, "y", 3)
End Sub

Function EvaluateFormula(formulaStr, ParamArray Variables_Values() As Variant) As Variant
    Dim i As Long
    
    For i = 0 To UBound(Variables_Values) Step 2
        formulaStr = Replace(formulaStr, Variables_Values(i), Variables_Values(i + 1))
    Next i
    
    EvaluateFormula = Evaluate(formulaStr)
    If IsError(EvaluateFormula) Then EvaluateFormula = formulaStr
End Function