Question

Given A={2,3,4}, B={2,5,6,7}.

A mapping A to B may be defined as $f=\{(2,5),(3,7),(4,6)\}$,

Is this mapping injective

Answer 1

$f=\{(2,5),(3,7),(4,6)\}$

$f$ is an injective mapping from $A$ to $B$ as distinct elements of set $A$ has distinct images in $B$.