// taxi-driver
// Taxi Driver
// Author: Constantine Sokol
// Complexity : O(N log N)
// Expected Verdict: AC

#include <iostream>
#include <cstdio>
#include <algorithm>

using namespace std;

const int MAXN = 200200;

int n;
int a, b;
int x[MAXN];
int y[MAXN];

long long process(int n, int x[]) {
	sort(x + 1, x + n + 1);
	long long result = 0;
	long long sum_prev = 0;
	for (int i = 1; i <= n; i++) {
		sum_prev += x[i];
		result += (long long)x[i] * i - sum_prev;
	}
	return result;
}

void solve() {
	scanf("%d", &n);
	scanf("%d%d", &a, &b);
	for (int i = 1; i <= n; i++) {
		int xs, ys;
		scanf("%d%d", &xs, &ys);
		x[i] = a * xs + b * ys;
		y[i] = a * xs - b * ys;
	}
	long long answer_x = process(n, x);
	long long answer_y = process(n, y);
	printf("%lld\n", (answer_x + answer_y) / 2);
}

int main() {
	int t; scanf("%d", &t);
	for (int i = 0; i < t; i++) {
		solve();
	}
	return 0;
}