a.Hệ số : -13,5.Biến : xyz.Bậc : 3

b.Nhóm 1 : 4x^3y^2;9x^3y^2

Nhóm 2 : -0,5x^2y^3;3/4x^2y^3

Dear Lia,

I hope this letter finds you well.I heard that you are feeding stressed about your upcoming exams,and I want you to know that it's completely normal to feel this way.To help manage your stress,try creading a study schedule to organise your time better.Remember to take regular breaks to relax your mind, and don't forget to practise deep breathing exercises.It can really help you stay calm.

You've worked hard , and I know you can handle this challenge.Good luck!

Best wishes,

1.The cat eats its food faster than the dog.

2.Although he plays guitar well,but he doesn't like performing in front of others.

1.I am fond of reading stories about famous scientists.

2.They spend a lot of time doing DIY projects with their parents.

3.Teen stress might come from conflicts or sibilings with friends.