Dev - C++ - que rutina puedo usar para hacer una ecuacion de 2do grado

#include <iostream>

#include <cmath>

using namespace std;

int main()

{

    float a, b, c;

    float x1, x2;

    cout << "Ecuacion de segundo grado: ";

    cout << "\nValor de a: "; cin >> a;

    cout << "Valor de b: "; cin >> b;

    cout << "Valor de c: " ; cin >> c;

    if( a < 0 ){

        x1 = -1 * ((-b + (sqrt( b * b - 4 * a * c ))) / 2 * a);

        x2 = -1 * ((-b - (sqrt( b * b - 4 * a * c ))) / 2 * a);

    }

    else {

        x1 = ((-b + (sqrt( b * b - 4 * a * c ))) / 2 * a);

        x2 = ((-b - (sqrt( b * b - 4 * a * c ))) / 2 * a);

    }

    cout << "\nX1: " << x1

         << "\nX2: " << x2;

    return 0;

}

#include <iostream>

#include <cmath>

using namespace std;

int main()

{

    float a, b, c;

    float x1, x2;

    cout << "Ecuacion de segundo grado: ";

    cout << "\nValor de a: "; cin >> a;

    cout << "Valor de b: "; cin >> b;

    cout << "Valor de c: " ; cin >> c;

    if( a < 0 ){

        a *= -1; b *= -1; c *= -1;

    }

    x1 = (( -b + (sqrt( b * b - 4 * a * c ))) / (2 * a) );

    x2 = (( -b - (sqrt( b * b - 4 * a * c ))) / (2 * a) );

    cout << "\nX1: " << x1

         << "\nX2: " << x2;

    return 0;

}