NEED HELP!!! with a) and b).

Please provide all the details. Thank you.

Problem 2. [10 points] The second associative law states that if A,B, and C are sets, then A(BC)= (AB)C. We prove this statement by proving the below two assertions. (a) Prove that A(BC)(AB)C. Hint: To prove this, start with an element xA(BC) and show that x(AB)C. (b) Prove that (AB)CA(BC). Do not use Venn diagrams in the above two proofs