//Coder: Balajiganapathi
#define TRACE
#define DEBUG

#include <algorithm>
#include <bitset>
#include <deque>
#include <cassert>
#include <cctype>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <functional>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <utility>
#include <vector>

using namespace std;

typedef long long ll;
typedef vector<int> vi;
typedef pair<int,int> pi;
typedef vector<string> vs;

// Basic macros
#define st          first
#define se          second
#define all(x)      (x).begin(), (x).end()
#define ini(a, v)   memset(a, v, sizeof(a))
#define re(i,s,n)  	for(int i=s;i<(n);++i)
#define rep(i,s,n)  for(int i=s;i<=(n);++i)
#define fr(i,n)     re(i,0,n)
#define repv(i,f,t) for(int i = f; i >= t; --i)
#define rev(i,f,t)  repv(i,f - 1,t)
#define frv(i,n)    rev(i,n,0)
#define pu          push_back
#define mp          make_pair
#define sz(x)       (int)(x.size())

const int oo = 2000000009;
const double eps = 1e-9;

#ifdef TRACE
    #define trace1(x)                cerr << #x << ": " << x << endl;
    #define trace2(x, y)             cerr << #x << ": " << x << " | " << #y << ": " << y << endl;
    #define trace3(x, y, z)          cerr << #x << ": " << x << " | " << #y << ": " << y << " | " << #z << ": " << z << endl;
    #define trace4(a, b, c, d)       cerr << #a << ": " << a << " | " << #b << ": " << b << " | " << #c << ": " << c << " | " << #d << ": " << d << endl;
    #define trace5(a, b, c, d, e)    cerr << #a << ": " << a << " | " << #b << ": " << b << " | " << #c << ": " << c << " | " << #d << ": " << d << " | " << #e << ": " << e << endl;
    #define trace6(a, b, c, d, e, f) cerr << #a << ": " << a << " | " << #b << ": " << b << " | " << #c << ": " << c << " | " << #d << ": " << d << " | " << #e << ": " << e << " | " << #f << ": " << f << endl;

#else

    #define trace1(x)
    #define trace2(x, y)
    #define trace3(x, y, z)
    #define trace4(a, b, c, d)
    #define trace5(a, b, c, d, e)
    #define trace6(a, b, c, d, e, f)

#endif

const ll mod = 1000000007;
ll M, R;

//Functions for performing modular operations
ll add(ll a, ll b) {
    return (a + b) % mod;
}

ll sub(ll a, ll b) {
    return add(a, mod - b);
}

ll mult(ll a, ll b) {
    a %= mod; b %= mod;
    return a * b % mod;
}

ll expo(ll a, ll p) {
    a %= mod;
    ll ret = 1;
    for(; p; p /= 2) {
        if(p & 1) ret = mult(ret, a);
        a = mult(a, a);
    }

    return ret;
}

ll inv(ll a) {
    return expo(a, mod - 2);
}

ll divide(ll a, ll b) {
    a %= mod; b %= mod;
    return mult(a, inv(b));
}

int main() {
    int t;
    cin >> t;
    while(t--) {
        cin >> M >> R;
        trace2(M, R);

        //See editorials for more details. The answer is 
        //(M^R - 1) / (M - 1) - R
        ll ans = sub(expo(M, R), 1);
        ans = divide(ans, sub(M, 1));
        ans = sub(ans, R);

        cout << ans << endl;
    }
    
	return 0;
}