mod = 998244353
def main():
    a, b, k = list(map(int, input().split()))
    if a == 0:
        return 0
    elif b == 0 or b == 1:
        if a < 0:
            return 0
        else:
            return a * k % mod
    elif b == -1:
        if a < 0:
            return -a * (k - 1) % mod
        else:
            return a * k % mod
    if 0 < a and 0 < b:
        return a * pow(b, k-1, mod) % mod
    elif 0 < a and b < 0:
        if k % 2:
            return a * pow(b, k-1, mod) % mod
        else:
            return 2 * a * pow(b, k-2, mod) % mod
    elif a < 0 and 0 < b:
        return 0
    else:
        if not k % 2:
            return -a * pow(-b, k-1, mod) % mod
        elif k == 1:
            return 0
        else:
            return -2 * a * pow(-b, k-2, mod) % mod

for _ in range(int(input())):
    print(main())