#include <bits/stdc++.h>
using namespace std;
const long long mod = 1e9 + 7;
int counting(long long a, long long b) {
  long long total = 1;
  while (b > 0) {
    if (b & 1) total = (total * a) % mod;
    b >>= 1;
    a = (a * a) % mod;
  }
  return total;
}
int main() {
  long long a, b, n, x, s;
  cin >> a >> b >> n >> x;
  if (a == 1) {
    s = (n % mod * b) % mod + x;
    cout << s % mod;
    return 0;
  }
  s = counting(a, n);
  long long s1 = counting(a - 1, mod - 2);
  long long s2 = (s - 1 + mod) % mod;
  s = s * x % mod;
  s = (s + s1 * s2 % mod * b % mod) % mod;
  cout << s % mod;
  return 0;
}
