# include <iostream>
# include <cstdio>
# include <queue>
# include <vector>
# include <stack>
# include <map>
# include <cmath>
# include <algorithm>
# include <stdio.h>
using namespace std;
 long long solve(long long b1,long long c1, long long s1, long long b2, long long c2, long long s2, long long n)
{
    long long i,j,uk1,uk2,mid;
    long long sum1,sum2,t,sum3,sum4;
    uk1 = s1;
    uk2 = s1+n-1;
    t = s2+n-1;
    sum1 = t*t + t*b2 + c2;
    sum2 = s1*s1 + b1*s1 + c1;
    if(sum1<=sum2)
    {
        return sum1;
    }
     t = s1+n-1;
      sum1 = s2*s2 + s2*b2 + c2;
    sum2 = t*t + b1*t + c1;
    if(sum2<=sum1)return sum2;
    while(1)
    {
        mid = (uk1+uk2)/2;
        t = n - (mid-s1+1) + s2 - 1;
        sum1 = mid*mid + b1*mid + c1;
        sum2 = t*t + t*b2 + c2;
        sum3 = (mid+1)*(mid+1) + b1*(mid+1) + c1;
        sum4 = (t+1)*(t+1) + b2*(t+1) + c2;
        if(sum1>sum4){uk2 = mid-1;continue;}
        if(sum2>sum3){uk1 = mid+1;continue;}
        if(sum1>sum2)return sum1;
        else
            return sum2;
    }
}
int main()
{
     ios_base::sync_with_stdio(false);
    cin.tie(NULL);
freopen ("sequences.out","w",stdout);
freopen ("sequences.in","r",stdin);
int q;
cin>>q;
int i,j;
long long b1,c1,s1,b2,c2,s2,n;
for(i=1;i<=q;i++)
{
    cin>>b1>>c1>>s1>>b2>>c2>>s2>>n;
    cout<<solve(b1,c1,s1,b2,c2,s2,n)<<endl;
}


}