4x - 7y = 3
x - 7y = -15​

10/10 recommend bring pads/tampons with you no matter what. im 16 & i’ve had mine since i was 12 and they’re still it regular, but id suggest using the glow app, many women use it for fertility reasons but i use mine specifically for the period tracking portion and it guesses when your next period will most likely be for the next two months. i dont believe theres any way to delay your period, so id say hope for the best but make sure to bring all of your stuff just incase. have a good cruise!