Fonction INDEX & EQUIV convertion EXCEL to VBA

With Sheets("BC")
    d = .[B18]
    c = .[B19]
End With
With Sheets("Budget")
    a = Application.Match(c, .[comptes], 0)
    b = Application.Match(d, .[departement], 0)
    x = Application.Index(.[c2:z501], a, b)
End With

Private Sub Worksheet_Change(ByVal Target As Range)
If Not Intersect(Target, [H5:H6]) Is Nothing And Target.Count = 1 Then
    [H9] = ""
    a = [H5]
    c = [H6]
    With Sheets("CAISSE")
        i = Application.Match(c, .[comptes], 0)
        j = Application.Match(a, .[agences], 0)
        x = Application.Index(.[b2:z501], i, j)
    End With
    If Not IsError(x) Then [H9] = x
End If
End Sub