Please help mr solve these discrete math probs. I really need it urgently thank u so much

5. Given sets A and B, define their symmetric difference as AAB = (4 B) U (B A). Use the set properties to show that AAB = AAB, indicate the property used in each step. (15 points) n+1 ifn=0 6. A function f:Z - Zisdefinedbyf(n) ={n-1ifn