Public Class Form1
    Dim x As Single
    Dim y As Single
    Dim D As Single
    Dim a As Single
    Dim b As Single
    Dim c As Single
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        a = TextBox1.Text
        b = TextBox2.Text
        c = TextBox3.Text
        D = (b * b) - (4 * a * c)
        If D >= 0 Then
            x = (-b + Math.Sqrt(D)) / (2 * a)
            y = (-b - Math.Sqrt(D)) / (2 * a)
            Label1.Text = "Дискриминант:" & D
            Label2.Text = "Корень x = " & x
            Label3.Text = "Корень y = " & y
        End If
        If D < 0 Then
            Label2.Text = "Дискриминант:" & D
            Label3.Text = "Корней нет"
            Label1.Text = ""

            msgbox("Дискриминант меньше нуля")
        End If
    End Sub
End Class