TIP: – One – One Function: – A function is said to be a one – one functions or an injection if different elements of A have different images in B.

So, is One – One function

⇔ a≠b

⇒ f(a)≠f(b) for all

⇔ f(a) = f(b)

⇒ a = b for all

Now, f : A → B, denotes a mapping such that

⇒ f = {(x,y):y = x + 3}

It can be written as follows in roster form

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

Hence this is injective mapping