Why won't this or any other way I have tried to write this line work?

Set x = rng.Subtotal(groupby:=1, Function:=xlSum)

Argument not optional error

Dim x as long

With Range(rn) 'tells range to use

rc = .Find(DateValue(dt), LookIn:=xlValues,
_lookat:=xlWhole).Rows.Row
'get row number of match

rng = ("b" & rc & ":" & "l" & rc)
'sets range to subtotal

Set x = rng.Subtotal(groupby:=1, Function:=xlSum)


End With