#include<iostream.h>
#include<conio.h>
main()
{
       cout<<"      Chuong trinh giai he pt 3 an\n\n\n";
       float a1,b1,c1,d1,a2,b2,c2,d2,a3,b3,c3,d3;
       cout<<"Nhap cac he so\n\n";
       cout<<"a1= "; cin>>a1;
       cout<<"b1= "; cin>>b1;
       cout<<"c1= "; cin>>c1;
       cout<<"d1= "; cin>>d1;
       cout<<"a2= "; cin>>a2;
       cout<<"b2= "; cin>>b2;
       cout<<"c2= "; cin>>c2;
       cout<<"d2= "; cin>>d2;
       cout<<"a3= "; cin>>a3;
       cout<<"b3= "; cin>>b3;
       cout<<"c3= "; cin>>c3;
       cout<<"d3= "; cin>>d3;
       float d,dx,dy,dz,x,w,z;
       d=a1*b2*c3+a2*b3*c1+a3*b1*c2-c1*b2*a3-c2*b3*a1-c3*b1*a2;
       dx=d1*b2*c3+d2*b3*c1+d3*b1*c2-c1*b2*d3-c2*b3*d1-c3*b1*d2;
       dy=a1*d2*c3+a2*d3*c1+a3*d1*c2-c1*d2*a3-c2*d3*a1-c3*d1*a2;
       dz=a1*b2*d3+a2*b3*d1+a3*b1*d2-d1*b2*a3-d2*b3*a1-d3*b1*a2;
       if (d==0)
          if (dx==0)
             if (dy==0)
                if (dz==0)
                   cout<<"\nHe pt co vo so nghiem\n";
                else cout<<"\n He pt vo nghiem\n";
             else cout<<"\nHe pt vo nghiem\n";
          else cout<<"\n He pt vo nghiem\n";
       else  
       {
            cout<<"\n He pt coa nghiem duy nhat\n";
            cout<<"x= "<<dx/d<<endl<<"y= "<<dy/d<<endl<<"z= "<<dz/d;
       }
       getch();
}