2x2 Systems

#include <iostream>

using namespace std;

int main()
{
    cout << "This is a programme about solving 2x2 system with 2 variables (x and y)." << endl;
    cout << "Give me the factors before x, y and the constant factor of 1st equation." << endl;
    double a1, b1, c1;
    double a2, b2, c2;
    cin >> a1;
    cin >> b1;
    cin >> c1;
    cout << "Now, do the same for the 2nd equation." << endl << endl;
    cin >> a2;
    cin >> b2;
    cin >> c2;

    // Για το πώς θα γραφεί η 1η εξίσωση
    if (a1>=0) {

        if(b1>=0){

            cout << a1 << "x +" << b1 << "y = " << c1 << endl;
        }

        else{

            cout << a1 << "x" << b1 << "y = " << c1 << endl;
        }
    }
    else{

       if(b1>=0){

            cout << a1 << "x +" << b1 << "y = " << c1 << endl;
        }

       else{

            cout << a1 << "x" << b1 << "y = " << c1 << endl;
       }
    }

    // Για το πως θα γραφτεί η 2η εξίσωση

    if (a2>=0) {

        if(b2>=0){

            cout << a2 << "x +" << b2 << "y = " << c2 << endl;
        }

        else{

            cout << a2 << "x" << b2 << "y = " << c2 << endl;
        }
    }
    else{

       if(b2>=0){

            cout << a2 << "x +" << b2 << "y = " << c2 << endl;
        }

       else{

            cout << a2 << "x" << b2 << "y = " << c2 << endl;
       }
    }

    float Dx = c1*b2 - c2*b1;
    float Dy = a1*c2 - a2*c1;
    float D = a1*b2 - a2*b1;

    if (D==0){

            if (c1/c2==a1/a2 && c1/c2==b1/b2){

                    cout << "This system has infinite solutions: ( x, (" << c1 << "-" << a1 << "x" << "/" << b1 << ") )" << endl;
            }
            else{
                    cout << "No solutions. Impossible system." << endl;
            }

    }

    else{
            cout << "Solution: " << endl;
            cout << "x = " << Dx/D << endl;
            cout << "y = " << Dy/D << endl;
    }

    return 0;
}