instruction:
In this task, you need to translate the given English sentence to Polish language.
question:
It has to be onto or essentially it has to map to 
answer:
Musi być "na", czyli musi odwzorowywać na każdy 


question:
If x is an arbitrary member of Rn, Let me write like this. 
answer:
Jeżeli x jest dowolnym elementem Rn -- zapiszę to tak. 


question:
And that really just takes a lot of practice. 
answer:

To naprawdę zabiera mnóstwo ćwiczenia.