private void button1_Click(object sender, EventArgs e)
{
if (Convert.ToDouble(textBox1.Text) == 0)
{
label6.Text = "Ошибка: a не может быть 0";
return;
}
else
{
label6.Text = "";
}
linear.SetA(Convert.ToDouble(textBox1.Text));
linear.SetB(Convert.ToDouble(textBox2.Text));
linear.CalculateAnswer();
label3.Text = $"Ответ: x = {linear.GetAnswer()}";
}