MOD = 998244353i64
read_line.to_i.times do
  puts solve() % MOD
end

def solve
  a, b, k = read_line.split.map(&.to_i64)
  ans = 0i64
  if a == 0
    return 0
  elsif a < 0
    if b >= 0
      return 0
    end
    if k == 1
      return 0
    end
    if b == -1
      return -a * (k - 1)
    end
    if k % 2 == 0
      return -a * pow(b.abs, k - 1)
    else
      return -a * 2 * pow(b.abs, k - 2)
    end
  else
    if b == -1 || b == 0 || b == 1
      return a * k
    elsif b < 0
      if k % 2 == 0
        return a * 2 * pow(b.abs, k - 2)
      else
        return a * pow(b.abs, k - 1)
      end
    else
      return a * pow(b, k - 1)
    end
  end
end

def inv(v : Int64)
  pow(v, MOD - 2)
end

def pow(v : Int64, p)
  ret = 1i64
  while p > 0
    if (p & 1i64) != 0
      ret *= v
      ret %= MOD
    end
    v *= v
    v %= MOD
    p >>= 1
  end
  ret
end