#include <bits/stdc++.h>
using namespace std;
long long exprap(long long bb, long long n) {
  if (n == 0) return 1;
  if (n % 2 == 0)
    return exprap((bb * bb) % 1000000007, n / 2) % 1000000007;
  else
    return (bb * (exprap(bb, n - 1)) % 1000000007) % 1000000007;
}
long long somapg(long long q, long long n) {
  if (q == 1) return n % 1000000007;
  if (n >= 1)
    return ((exprap(q, n) - 1) * exprap(q - 1, 1000000007 - 2)) % 1000000007;
  else
    return 0;
}
int main() {
  long long a, b, n, x;
  scanf("%lld %lld %lld %lld", &a, &b, &n, &x);
  printf("%lld\n", (x * exprap(a, n) + b * somapg(a, n)) % 1000000007);
  return 0;
}
