Private Sub Command1_Click()
Dim a, b, c, dert As Integer
Dim p, r, x1, x2 As Single
a = Val(Text1.Text)
If a = 0 Then MsgBox "a 不能为0": Exit Sub
b = Val(Text2.Text)
c = Val(Text3.Text)
dert = b * b - 4 * a * c
p = -b / (2 * a)
If dert >= 0 Then
If dert > 0 Then
r = Sqr(dert) / (2 * a)
x1 = p + r
x2 = p - r
Else
x1 = p
x2 = p
End If
Label5.Caption = "x1=" & x1
label6.Caption = "x2=" & x2
Else
r = Sqr(-dert) / (2 * a)
one = "x1=" & p
Label5.Caption = one&"+"&r&"i"&chr(13)&"x2="&p&"-"&r&"i" 请问这语句有错误吗
End If
End Sub

你试一下这个：
Private Sub Command1_Click()
Dim a, b, c, dert As Integer
Dim p, r, x1, x2 As Single
a = Val(Text1.Text)
If a = 0 Then MsgBox "a 不能为0": Exit Sub
b = Val(Text2.Text)
c = Val(Text3.Text)
dert = b * b - 4 * a * c
p = -b / (2 * a)
If dert >= 0 Then
If dert > 0 Then
r = Sqr(dert) / (2 * a)
x1 = p + r
x2 = p - r
Else
x1 = p
x2 = p
End If
Label5.Caption = "x1=" & x1
label6.Caption = "x2=" & x2
Else
r = Sqr(-dert) / (2 * a)
Label5.Caption = "x1=" & p & "+" & r & "i" + Chr(13) + Chr(10) + "x2=" & p & "-" & r & "i"
End If
End Sub
应该是换行的函数出问题了

其实不用换行更好不是吗？当是复数解时，也把它分别放在两个标签文本框里不是很好吗？而且也不会留下前一次的计算结果痕迹。所以，将最后一个
Label5.Caption = "x1=" & p & "+" & r & "i" + Chr(13) + Chr(10) + "x2=" & p & "-" & r & "i"
改为：
Label5.Caption = "x1=" & p & "+" & r & "i"
Label6.Caption = "x2=" & p & "-" & r & "i"
嗯，应该是没问题了。

现在没错了 谢了啊 是那个地方出错了 但我用＆这个连接符号怎么不行啊

用＆也可以了  可能是我粗心 输入错误