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

int gcd(int a, int b)
{
    while(b!=0)
    {
        int tem;
        tem=b;
        b=a%b;
        a=tem;
    }
    return a;
}

int main()
{
    int a, b;
    int tc;
    cin>>tc;
    while(tc--)
    {
        cin>>a>>b;
        int gd, lcm;
        gd=gcd(a, b);
        lcm=(a*b)/gd;
        if(gd%a==0&&lcm%b==0) cout<<gd<<" "<<lcm<<endl;
        else cout<<-1<<endl;
    }
    return 0;
}