Question

S is a subset within a universal set, U. If S = {x, y, 4, 9, ?), which could describe U? U = {keys on a keyboard}

Answer 1

Answer:

U = {keys on a keyboard}

Step-by-step explanation:

This is because x, y, 4, 9, ? are all keys located on a keyboard.

Answer 2

Since U is a universal set where S is its subset, then set U should consist of all the letters, numbers and punctuation mark in a keyboard. In other words, universal set U consists of the following elements:
U = (0, 1, 2, 3, 4, 5, 6, 7, 8, 9)
U = (x| x comprised of all the letters in the alphabet fro a to z)
U = (!,.,,,?,!:,;,",',-)