#include <bits/stdc++.h>
using namespace std;
const int MOD = 1e9 + 7;
long long int p(long long int bas, long long int exp) {
  if (exp == 0) return 1LL;
  long long int t = p(bas, exp >> 1LL);
  t = (t * t) % MOD;
  if (exp & 1LL) t = (t * bas) % MOD;
  return t;
}
int main() {
  ios_base::sync_with_stdio(false);
  long long int A, B, n, x;
  cin >> A >> B >> n >> x;
  long long int ans = (p(A, n) * x) % MOD;
  if (A == 1) {
    long long int tmp = n % MOD;
    ans = (ans + B * tmp) % MOD;
  } else {
    long long int tmp = (p(A, n) - 1 + MOD) % MOD;
    tmp = (tmp * B) % MOD;
    ans = (ans + tmp * p((A - 1 + MOD) % MOD, MOD - 2)) % MOD;
  }
  cout << ans << endl;
  return 0;
}
