939 B | 905 chars
"""
[30143: Cookie Piles](https://www.acmicpc.net/problem/30143)
Tier: Bronze 4
Category: math
"""
import sys
from math import sqrt, pi, sin, factorial, ceil, floor
from datetime import datetime, timedelta
SYS_INPUT = True
RECURSION_LIMIT = 10 ** 7
SET_RECURSION = False
BLANK = " "
if SET_RECURSION:
sys.setrecursionlimit(RECURSION_LIMIT)
inp = lambda : sys.stdin.readline().rstrip() if SYS_INPUT else input()
mii = lambda : [*map(int,inp().split())]
mfi = lambda : [*map(float,inp().split())]
ii = lambda : int(inp())
fi = lambda : float(inp())
isplit = lambda : inp().split()
p = print
def gcd(a, b): return gcd(b, a % b) if b > 0 else a
def lcm(a, b): return a * b // gcd(a, b)
def solve():
n, a, d = mii()
# n : 수열의 갯수
# a : 시작 숫자
# d : 공차
# 전체 수열의 합
print(n * a + n * (n-1) * d // 2)
if __name__ == "__main__":
tc = ii()
for t in range(1, tc+1):
ret = solve()