import sys
input = lambda :sys.stdin.readline()[:-1]
ni = lambda :int(input())
na = lambda :list(map(int,input().split()))
yes = lambda :print("yes");Yes = lambda :print("Yes");YES = lambda : print("YES")
no = lambda :print("no");No = lambda :print("No");NO = lambda : print("NO")
#######################################################################

def naive(a, b, K):
    ans = 0
    for k in range(K + 1):
        for i in range(1 << k):
            z = 0
            for j in range(k):
                if i >> j & 1:
                    z += a
                else:
                    z *= b
            # print(k, bin(i), z)
            ans = max(ans, z)
    return ans

def test(a, b, k):
    if a == 0:
        return 0
    elif b == 0:
        return max(0, a * k)
    elif b == 1:
        return max(0, a * k)
    elif b > 1:
        if a <= 0:
            return 0
        else:
            return a * b ** (k - 1)
    elif b == -1:
        if a > 0:
            return a * k
        else:
            return -a * (k - 1)
    else:
        if a > 0:
            if k % 2 == 1:
                return a * b ** (k-1)
            else:
                return 2 * a * b ** (k-2)
        else:
            if k % 2 == 0:
                return a * b ** (k-1)
            elif k == 1:
                return 0
            else:
                return 2 * a * b ** (k-2)

mod = 998244353
def solve(a, b, k):
    if a == 0:
        return 0
    elif b == 0 or b == 1:
        if a > 0:
            return a * k % mod
        else:
            return 0
    elif b > 1:
        if a < 0:
            return 0
        else:
            return a * pow(b, k-1, mod) % mod
    elif b == -1:
        if a > 0:
            return a * k % mod
        else:
            return (-a * (k - 1) )% mod
    else:
        if a > 0:
            if k % 2 == 1:
                return a * pow(b, k-1, mod) % mod
            else:
                return 2 * a * pow(b, k-2, mod) % mod
        else:
            if k % 2 == 0:
                return a * pow(b, k-1, mod) % mod
            elif k == 1:
                return 0
            else:
                return 2 * a * pow(b, k-2, mod) % mod


# from random import randint
# for _ in range(100000):
#     k = randint(1, 3)
#     a = randint(-5, 5)
#     b = randint(-5, 5)
#     r1 = naive(a, b, k)
#     r2 = test(a, b, k)
#     if r1 != r2:
#         print(a, b, k)
#         print(r1, r2)
#         break

for _ in range(ni()):
    a, b, k = na()
    print(solve(a, b, k))