Option Explicit
Private Sub Worksheet_Change(ByVal c As Range)
If c.Address = "$K$19" Then
Select Case c
Case 1: Sheets("Feuil1").Visible = -1: Sheets("Feuil2").Visible = 2
Case 2: Sheets("Feuil1").Visible = 2: Sheets("Feuil2").Visible = -1
Case Empty: Sheets("Feuil1").Visible = 2: Sheets("Feuil2").Visible = 2
End Select
End If
End Sub