Doubt

[soniya duge]

Let f:R→R be a function and f(x)=|(x+4)(4x−10)|. Which of the following is(are) true?

f is an injective function

f is a surjective function

f is a bijective function

 None of these

The answer over here is None of these.

But if instead of  f:R→R it would have been  f:R→N, then wouldn't the answer be 

'f is a surjective function'

Regards,

Soniya Duge