Dear Pattrick,

Can you help me? The homework was given by the teacher was too difficult for me to do. I have tried to do it for many times but no answered. If you agree, can you meet me at the library of our school. 

I'm look forward to receiving your answer.

XYZ

Hi Patrick,

How are you now? Hope you are fine. I know you are very good at Maths, aren't you? Now, I am doing my homework but this question is so difficult that I cannot do it. I cannot do it because at the time my teacher was teaching my class this lesson, I stayed at home because of my sickness.  Can you help me with this?  If yes, we can meet at the library near your house.

If you agree, please write to me soon. 

Hope your letter

Best wishes, 

phuc anh