In the first pair, neither is correct. Borrow/lend/loan causes a lot of confusion for ESL learners. Although the concepts are closely related, you cannot borrow a loan. Examples of correct sentences would read:
Have you experienced borrowing from another lender?
Have you obtained a loan from any other lender?
In the second pair, the first sentence is more correct, but the word only needs to be moved to more clearly modify the word five:
If we could improve in only five of the above areas, which should we focus on?
Technically, the second clause should read "on which should we focus?" to be truly grammatically correct. However, in informal English, saying "which should we focus on?" is acceptable.
Hope this helps,
Student or Learner