#include <iostream>
#include<math.h>
using namespace std;

int main()
{
    int n, i;
    double sum_xi=0, sum_fi=0, sum_xi2=0, sum_xifi=0;
    cout<<"Wpisz n: ";
    cin>>n;
    double xi[n+1], fi[n+1], w, w0, w1, a0, a1;
    cout<<"Wpisz elementy xi;\n";
    for(i=0; i<=n; i++){
        cout<<"x"<<i<<": ";
        cin>>xi[i];
        cout<<"\n";
    }
    cout<<"Wpisz elementy fi;\n";
    for(i=0; i<=n; i++){
        cout<<"f"<<i<<": ";
        cin>>fi[i];
        cout<<"\n";
    }
    for(i=0; i<=n; i++){
        sum_xi=sum_xi+xi[i];
        sum_fi=sum_fi+fi[i];
        sum_xi2=sum_xi2+pow(xi[i],2);
        sum_xifi=sum_xifi+(xi[i]*fi[i]);
    }
    w=((n+1)*sum_xi2)-(pow(sum_xi,2));
    w0=(sum_fi*sum_xi2)-(sum_xi*sum_xifi);
    w1=((n+1)*sum_xifi)-(sum_fi*sum_xi);
    a0=w0/w;
    a1=w1/w;
    cout<<"g(x)="<<a0<<"+"<<a1<<"x"<<endl;
    return 0;
}