The function $f : \mathbb{R} \to \mathbb{R}$, $f ( x ) = \frac { x ^ { 2 } + 2 x - 15 } { x ^ { 2 } - 4 x + 9 } , x \in \mathbb { R }$ is\\
(1) one-one but not onto.\\
(2) both one-one and onto.\\
(3) onto but not one-one.\\
(4) neither one-one nor onto.