a market researcher collecting data on 100 house holds finds that 81 have cable television,65 have high speed internet and 56 have both. How many house holds have neither cable television nor hugh internet speed​

Let d be the domain and let ƒ be the possible function. determine if the relation is an example of a function. d = {x| x is a date, expressed in day/month/year} ƒ(x) = temperature in seattle washington on that date