If a function f:R→Rf: \mathbb{R} \rightarrow \mathbb{R}f:R→R is defined as f(x)=2x+3f(x) = 2x + 3f(x)=2x+3, which of the following are true?
fff is injective (one-to-one)
fff is surjective (onto)
fff is a bijection
fff is not a function