Sharing Our Innermost Thoughts

I need advise, so this past few weeks i’ve been failing math quiz and activity and my best friend who’s good at math sit beside me today for final exam at math and if i fail one more time i might get an F, So the teacher hand us a worksheet, I looked at it and Its too hard for me and as soon as my friend took his worksheet he already started answering it at his Scratch paper and then 30 mins have passed he finished he looked around to see if our teacher was around and he quickly grabbed my scratch paper and he swapped it with his and i looked at it and the whole answer was in there and there’s a note saying “tear that paper to pieces and throw it at the trash can after you finished copying it.” i look at him and he’s just started answering his worksheet so i copied it, 41 mins later i finished and my friend was still answering and so i did as he told few minutes later he finished and we both waited for about 45 mins for the exam to finished. I thank him alot after exam and 5 hours later our math teacher send our scores at the gc and i got perfect score while my friend has 2 mistake, how can i repay him? TOt