Answer: f(x₁) = f(x₂) implies x₁ = x₂.
- A f(x₁) = f(x₂) implies x₁ = x₂
- B Every element of B has a preimage
- C The range equals the codomain
- D A and B have the same number of elements
Correct answer: A. f(x₁) = f(x₂) implies x₁ = x₂
Explanation: Injectivity means distinct inputs never share an output.
Concept context
Types of relations, equivalence classes, one-one and onto functions, composition, and invertible functions