Question

The function $f:N\to N$, where $N$ is the set of natural numbers, defined by $f\left(x\right)=7x+11$ is

• A. injective
• B. surjective
• C. bijective
• D. none of these

Answer 1

The correct option is A injective

$f\left(x\right)=7x+11$ is strictly increasing
Therefore, it is one-one.
For $x\in N$, $f\left(x\right)\in N$
Therefore, it is onto and thus it is injective.