Which of the following are examples of the null set?
B = {x : x ϵ N, 2x + 3 = 4}.
Natural numbers = 1, 2, 3, 4, 5, 6,…
If x = 1, then 2x + 3 = 2(1) + 3 = 2 + 3 = 5 ≠ 4
∴ no elements in the set B because the equation 2x + 3 = 4 is not satisfied by any natural number of x.
∴ It is a null set.