[说明] 某小型家电超市开发了下面的程序，用以实现商品提货信息的汇总和输出功能。程序的运行界面如下图所示：

程序界面包含两个控件数组，分别是提货商品复选框控件数组Check1以及提货数量文本框控件数组Text1(相同下标的复选框和文本框相对应)，提货清单的显示由List控件实现，按钮“打印清单”和“清除”分别名为Command1和Command2。[Visual Basic代码]’提货商品复选框的单击事件响应代码Private Sub Check1_Click(Index As Integer)If Check1 (Index). Value = 1 Then (1) . SetFocusEnd Sub’按钮“打印清单”的单击事件响应代码Private Sub Command1_Click() Dim i, n, price As Integer, sum As Long, title As String sum = 0 For i = O To 4 Select Case i Case 0: title ="电视机": price = 3580 Case 1: title ="微波炉": price = 660 Case 2: title ="电冰箱": price = 1850 Case 3: title ="DVD":price = 2880 Case 4: title ="空调": price = 2500 End Select If (2) = 1 And Textl(i). Text ＜ ＞ " " Then (3) title & Text1(i).Text & "台" n = n + Val(Textl(i)) sum = (4) End If Next i If sum ＜ ＞ 0 Then(3) "共:" & n &"台," &"合计金额:"& sum &"元。" End IfEnd Sub’按钮“清除”的单击事件响应代码Private Sub Command2_Click() (5) End Sub

当x=______时，代数式2x²-4x与代数式x²-2x+8的值相等．