Question

let f :N ~N be defined by f(x) =2x+3,x€N then find the images 2,3​

Answer 1

Step-by-step explanation:

We know that,

f(x)=2x+3

now,

f′(x)=2>0 for all x

hence f(x) in always increasing function hence is injective

and for surjective  

consider x1<x2

lets consider f(x1)<f(x2)

2(x1)+3<2(x2)+3

hence we get x1<x2

hence function is surjective as well 

the final results are 

f(x) is a injective and surjective function as well