Question

Prove that empty set is a sub set of set x?

Answer 1

Answer:

The set A is a subset of the set B if and only if every element of A is also an element of B. If A is the empty set then A has no elements and so all of its elements (there are none) belong to B no matter what set B we are dealing with.

Answer 2

null set/empty set is a sub set of all sets...

consider a set x={1,2}

the subsets of this sets are {1},{2},{1,2} ∅