2-1

Could you clarify what you mean by "2-1"?

• If you meant 2 − 1, the result is 1.
• If you mean Chapter/Section 2.1 or Problem 2.1 from your textbook, please tell me the course and the book (or paste the problem text) and I’ll walk you through it.
• If you have a specific 2.1 problem, paste it here and I’ll solve it step by step.