I basically set up my program as is and it does not run correctly. Right now I am recieiving a "Run Time Error '13': Type mismatch". I don't have the MSDN library because I didn't install it when I first bought the program. If any of you could give some input, that would be great. I have made a few alternations but here is the way I currently have it set up.

Dim X1 As String
Dim X2 As String
Dim a As String
Dim b As String
Dim c As String


Private Sub cmdCalculate_Click()
txtValueA = a
txtValueB = b
txtValueC = c
If X1 = (-b + Sqr(b ^ 2 - 4 * a * c)) / 2 * a Then
lblFirst.Caption = X1
End If
If X2 = (-b - Sqr(b ^ 2 - 4 * a * c)) / 2 * a Then
lblSecond.Caption = X2
End If
End Sub