"Exactly", "certainly", and "absolutely" are all similar in meaning and are often used interchangeably to emphasize agreement or certainty. However, there are slight differences in their usage:

"Exactly" is typically used to stress that something is precise or accurate."Certainly" is used to express confidence or assurance in a statement."Absolutely" is used to convey strong agreement or affirmation.

Какая разница? - translates to "What difference does it make?" in English, implying that the details or distinctions being discussed are inconsequential or unimportant.