Natural numbers = 1, 2, 3, 4, 5, 6,…

If x = 1, then x2 + 1 = (1)2 + 1 = 1 + 1 = 2 ≠ 0

∴ 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.

Which of the following are examples of the null set? D = {x : x ε N, x2 + 1 = 0}.

Which of the following are examples of the null set? D = {x : x ε N, x2 + 1 = 0}.

Natural numbers = 1, 2, 3, 4, 5, 6,…

If x = 1, then x2 + 1 = (1)2 + 1 = 1 + 1 = 2 ≠ 0

∴ 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.