import math

Q = int(input())

for q in range(Q):
	X, N, d = map(int, input().split())
	
	if math.gcd(X, d) != 1:
		print("inf")
		continue
	
	ans = max((X - 1) * (d - 1), min(X - 1, N - 1) * d)
	print(-1 if ans == 0 else ans)