Respuesta :
y = 75 - 6d......d = number of days
after 9 days.....d = 9
y = 75 - 6(9)
y = 75 - 54
y = 21....so there are 21 after 9 days
after 9 days.....d = 9
y = 75 - 6(9)
y = 75 - 54
y = 21....so there are 21 after 9 days