Question

If $f:Z\to Z$ is such that $f\left(x\right)=6x-11$ then $f$ is

• A. injective but not surjective
• B. surjective but not injective
• C. bijective
• D. neither injective nor surjective

Answer 1

Answer: (A)

injective but not surjective

$f\left(x\right)=6x-11$ is always increasing.
Therefore, it is one-one.
But $f\left(x\right)$ cannot take all values in $Z$. Hence, it is not onto.
Ans: A