#include <bits/stdc++.h>
using namespace std;
template <typename Arg1>
void __f(const char* name, Arg1&& arg1) {
  cerr << name << " : " << arg1 << '\n';
}
template <typename Arg1, typename... Args>
void __f(const char* names, Arg1&& arg1, Args&&... args) {
  const char* comma = strchr(names + 1, ',');
  cerr.write(names, comma - names) << " : " << arg1 << " | ";
  __f(comma + 1, args...);
}
int inf = 0x3f3f3f3f;
long long infl = 0x3f3f3f3f3f3f3f3fLL;
long double infd = 1.0 / 0.0;
const long long MOD = 1e9 + 7;
const double pi = 2 * acos(0.0);
long long modi(long long a, long long n) {
  long long x = 1;
  while (n) {
    if (n & 1) x = (x * a) % MOD;
    n >>= 1;
    a = (a * a) % MOD;
  }
  return x;
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  ;
  int tt = 1;
  while (tt--) {
    long long a, b, n, x;
    cin >> a >> b >> n >> x;
    long long as = (((a * x) % MOD) + b) % MOD;
    long long le = (x * modi(a, n)) % MOD;
    long long ri = a == 1ll ? ((b * (n % MOD)) % MOD)
                            : ((b * (((((modi(a, n) - 1 + MOD) % MOD)) *
                                      (modi(a - 1, MOD - 2))) %
                                     MOD)) %
                               MOD);
    cout << ((((le + ri) % (MOD)) + (MOD)) % (MOD)) << '\n';
  }
  return 0;
}
