C++ Quadratic Equation

#include <iostream>

#include <cmath>

using namespace std;

int main()

{

double a, b, c, discriminant, x1, x2, imaginary;

    cin >> a >> b >> c;

discriminant = b*b - 4*a*c;

if (a == 0)

 {

cout << "Can't divide by 0!" << endl;

}

        else if (discriminant > 0)

        {

            x1 = (-b + sqrt(discriminant)) / (2*a);

            x2 = (-b - sqrt(discriminant)) / (2*a);

            cout << "x1 = " << x1 << endl;

            cout << "x2 = " << x2 << endl;

        }

    else if (discriminant == 0)

    {

        x1 = (-b + sqrt(discriminant)) / (2*a);

        cout << "x1 = x2 =  " << x1 << endl;

    }

        else if (imaginary = -b/(2*a))

        {

            cout << "Values are imaginary!"  << endl;

        }

return 0;

}