#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
#define _for(i,a,b) for(register int (i)=(a);(i)<=(b);(i)++)
#define For(i,a,b) for(register int (i)=(a);(i)>=(b);(i)--)
#define INF 0x7fffffff
#define il inline
#define rg register
void work(){
    ll a,b; scanf("%lld%lld",&a,&b);
    if(a<b) swap(a,b);
    if(a==b){ 
        if(a==1) puts("-1 -1");
        else printf("2 %lld\n",a);
        return ;
    }
    ll k=a-b,minn=1e10,maxx=-1;
    for(ll i=1;i*i<=k;i++){
        if(k%i==0) {
            if(i!=1) minn=min(minn,i),maxx=max(maxx,i);
            if(i!=k) minn=min(minn,k/i),maxx=max(maxx,k/i);
        }
    }
    if(minn==1e10)  printf("-1 ");
    else printf("%lld ",minn);
    printf("%lld\n",maxx);
}
int main(){
    int T;
    scanf("%d",&T);
    while(T--) work();
    return 0;
}