# Math Help - Set Proofs

1. ## Set Proofs

Let A and B be sets. Show that ( A ∩ B) ⊆ A. Prove first the left side ⊆ right side. Then right side ⊆ left side.

2. Is this a true statement $x\in A\rightarrow x\in A?$

3. yes

4. So if $x\in A\cap B$ then $x\in A\text{ and }x\in B$. Thus ?

5. Then they are subsets

6. You don't need to prove right to left, and we can't anyway.

7. Originally Posted by lm6485
Then they are subsets
Yes, but say specifically what you mean by "they", and say why "x in A and x in B" justifies that (it might be so obvious that you miss the need to say it).