Option Explicit
Dim a#, b#, c#, x#, x1#, x2#

Private Sub Command1_Click()
a = Text1.Text
b = Text2.Text
c = Text3.Text
If a = 0 Then
x = -c / b
x1 = x
Text4.Text = x1
ElseIf a <> 0 & b * b - 4 * a * c = 0 Then
x = -b / 2 * a
x1 = x2 = x
Text4.Text = x1
Text5.Text = x2
ElseIf a <> 0 & b * b - 4 * a * c > 0 Then
x = -b + (b * b - Sqr(4 * a * c)) / 2 * a & x = -b - (b * b - Sqr(4 * a * c)) / 2 * a
x1 = x & x2 = x
Text4.Text = x1
Text5.Text = x2
ElseIf a <> 0 & b * b - 4 * a * c < 0 Then
x = "有虚根"
x1 = x
Text4.Text = x1

End If
End Sub

Private Sub Command2_Click()
End
End Sub

Private Sub Form_Load()

End Sub

毛病不是一点。。。是相当的多。。帮你改好了，因为实在错的太多，不一一解释了，红色的地方是我修改的

Option Explicit
Dim a#, b#, c#, x#, x1#, x2#


Private Sub Command1_Click()
    a = Val(Text1.Text)
    b = Val(Text2.Text)
    c = Val(Text3.Text)
    If a = 0 Then
        x = -c / b
        x1 = x
        Text4.Text = x1
        Text5.Text = \"\"
    ElseIf a <> 0 And b * b - 4 * a * c = 0 Then
        x = -b / (2 * a)
        x1 = x
        x2 = x
        Text4.Text = x1
        Text5.Text = x2
    ElseIf a <> 0 And b * b - 4 * a * c > 0 Then
        x1 = (-b + Sqr(b * b - 4 * a * c)) / (2 * a)'求根公式都能写错，我晕
        x2 = (-b - Sqr(b * b - 4 * a * c)) / (2 * a)
        Text4.Text = x1
        Text5.Text = x2
    ElseIf a <> 0 And b * b - 4 * a * c < 0 Then
        Text4.Text = \"有虚根\"
        Text5.Text = \"\"
    End If
End Sub

Private Sub Command2_Click()
End
End Sub

[此贴子已经被作者于2007-10-20 13:09:24编辑过]

哦.如果我要是求虚根你看这个语句可不.我不知道哪里又出问题了?
x1 = (-b) / (2 * a) & "+" & Sqr(-(b * b - 4 * a * c)) / (2 * a) & "i"
x2 = (-b) / (2 * a) & "-" & Sqr(-(b * b - 4 * a * c)) / (2 * a) & "i"

呵呵，空虚中，只能找事做了

用引号括住的肯定是字符串

编程的语法都是有严格规定的，不能想当然，比如vb表示”条件与“是用and，你就不能用"&"

基本数据类型是没有虚数的，double只能表示实数