Option Explicit
Sub Dernière_ligne_où_x_apparaît()
Dim i As Long
Application.ScreenUpdating = False
Columns("a:b").Insert
Selection.Insert Shift:=xlToRight, CopyOrigin:=xlFormatFromLeftOrAbove
For i = Cells(Rows.Count, "c").End(xlUp).Row To 1 Step -1
If Range("c" & i) Like "*+*" And Range("c" & i) Like "*tk*" Then Range("c" & i).Offset(, -2) = Range("A" & i).Row
Next
[b1].FormulaR1C1 = "=MAX(C[-1])"
MsgBox "Ligne : " & [b1].Value
Columns("a:b").Delete
Application.ScreenUpdating = True
End Sub