#include<bits/stdc++.h>
using namespace std;
using LL = long long;
const int mo = 1e9 + 7;
const int maxn = 2e5 + 5;


int main() {
    int T;
    scanf("%d", &T);
    while(T--) {
        int a, b;
        scanf("%d%d", &a, &b);
        if(b > a) {
            swap(a, b);
        }
        if(a == b && a != 1) {
            printf("2 %d\n", a);    
        }
        else {
            int up = sqrt(a - b) + 1;
            int d = a - b;
            int low = a + 1, tup = -1;
            for(int i = 1; i <= up; i++) {
                if(d % i == 0) {
                    if(i >= 2 && (a / i - b / i) * i == d) {
                        low = min(low, i);
                        tup = max(tup, i);
                    }
                    int c = d / i;
                    if(c >= 2 && (a / c - b / c) * c == d) {
                        low = min(low, c);
                        tup = max(tup, c);
                    }
                }
            }
            if(tup == -1) {
                printf("-1 -1\n");
            }
            else {
                printf("%d %d\n", low, tup);
            }
        }
    }
    return 0;
}