Quadratic Formula and A= x1+2*x2

#include<iostream>
#include <math.h>

using namespace std;

double returnA(double a, double b, double c){

    double  x1, x2, A2;
    double D = b*b - 4*a*c;

if(a==0){
    cout<< "\"a\" ne moje da e 0!"<< endl;
}else if(D<0){
    cout << "Nyama reshenie!";
}else{
x1 = (-b + sqrt(b * b - 4 * a * c)) / (2 *a);

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

A2 = x1 + 2*x2;

cout << "A=" << A2;
    }

}

int main(){

double a, b, c;

cout << "a= ";
cin >> a;
cout << "b= ";
cin >> b;
cout << "c= ";
cin >> c;

returnA(a, b, c);


}