Formula:-

(i) A function is one-one function or an injection if

f(x)=f(y)

⇒ x=y for all x, y ∈ A

or f(x)f(y)

⇒ xy for all x, y ∈ A

(a) It is not one-one function as it has same image on x axis

(b) It is one-one function s it have unique image