#include <bits/stdc++.h>
using namespace std;

int main(void) {
    int T; scanf("%d", &T);
    while (T--) {
        int a, b; scanf("%d%d", &a, &b);

        if (a == b && a >= 2) {
            printf("%d %d\n", 2, a);
            continue;
        }

        int d = max(a, b) - min(a, b);
        int mn = (int)1e9+10, mx = 0;
        for (int i=1; i*i<=d; i++) if (d % i == 0) {
            if (i > 1 && a % i == b % i) mn = min(mn, i), mx = max(mx, i);
            if (d/i > 1 && a % (d/i) == b % (d/i)) mn = min(mn, d/i), mx = max(mx, d/i);
        }
        if (mn <= mx) printf("%d %d\n", mn, mx);
        else printf("-1 -1\n");
    }
    return 0;
}

// a = xc + r
// b = yc + r
// c | b - a