import std;

void main () {
    const long MOD = 998244353;
    int caseNum = readln.chomp.to!int;
    auto ans = new long[](caseNum);
    foreach (caseId; 0 .. caseNum) {
        int A, B, K;
        readln.read(A, B, K);

        if (B == 0 || B == 1) {
            if (0 <= A) {
                ans[caseId] = 1L * A * K % MOD;
            }
            else {
                ans[caseId] = 0;
            }

            continue;
        }

        if (B == -1) {
            if (0 <= A) {
                ans[caseId] = 1L * A * K % MOD;
            }
            else {
                ans[caseId] = 1L * -A * (K - 1) % MOD;
            }
            continue;
        }

        if (2 <= B) {
            if (0 <= A) {
                ans[caseId] = A * mod_pow(B, K - 1, MOD) % MOD;
            }
            else {
                ans[caseId] = 0;
            }
            continue;
        }

        if (B <= -2) {
            long rem = K;
            if (0 <= A) {
                long v = A;
                rem--;

                if (rem % 2 == 1) {
                    v += A;
                    rem--;
                }

                v *= mod_pow(-B, rem, MOD);
                v %= MOD;
                ans[caseId] = v;
            }
            else {
                if (rem == 1) {
                    ans[caseId] = 0;
                }
                else {
                    long v = -A;
                    rem--;

                    if (rem % 2 == 0) {
                        v += -A;
                        rem--;
                    }

                    v *= mod_pow(-B, rem, MOD);
                    v %= MOD;
                    ans[caseId] = v;
                }
            }
            continue;
        }

        enforce(caseId < 0);
    }

    writefln("%(%s\n%)", ans);
}

void read (T...) (string S, ref T args) {
    import std.conv : to;
    import std.array : split;
    auto buf = S.split;
    foreach (i, ref arg; args) {
        arg = buf[i].to!(typeof(arg));
    }
}

long mod_pow (long a, long x, const long MOD)
in {
    assert(0 <= x, "x must satisfy 0 <= x");
    assert(1 <= MOD, "MOD must satisfy 1 <= MOD");
    assert(MOD <= int.max, "MOD must satisfy MOD*MOD <= long.max");
}
do {
    // normalize
    a %= MOD; a += MOD; a %= MOD;

    long res = 1L;
    long base = a;
    while (0 < x) {
        if (0 < (x&1)) (res *= base) %= MOD;
        (base *= base) %= MOD;
        x >>= 1;
    }

    return res % MOD;
}