C++ quadratic formula

#include<iostream>
#include<cstdlib>
#include<cmath>
int main()
{

    double a, b, c, x1, x2;
    std::cout<<"Helloworld"<<std::endl;

    a=2.00;
    b=8.00;
    c=6.00;

    std::cout<<"Heres the quadratic formula:"<<std::endl;
    std::cout<<a<<"x^2"<<'+'<<b<<'x'<<'+'<<c<<endl;

    x1=b+(sqrt(pow(b, 2)-4*a*c))/(2*a);
    x2=-b+(sqrt(pow(b, 2)-4*a*c))/(2*a);

    std::cout<<x1<<" or"<<x2<<endl;

    return EXIT_SUCCESS;
}