Let f: R→R be defined as f(x)=5x^2. Choose the correct answer :

The correct answer is Option (4) → f is neither one-one nor onto

$f(x)=5x^2$

(1) Not one one

as at $x = -1, 1$

$f(-1)=5=f(1)$ but $1≠-1$

(2) Not onto

as for $f(x) = -25$

$x^2=-5$ ⇒ no. x exists