If the Function Is One-To-One, Find Its Inverse $$f ( x ) = 2 x ^ { 2 } - 9 , x \geq 0$$

Multiple Choice

If the function is one-to-one, find its inverse. If not, write "not one-to-one."
- $$f ( x ) = 2 x ^ { 2 } - 9 , x \geq 0$$

A) $f ^ { - 1 } ( x ) = \frac { 2 } { \sqrt { x } + 4 }$
B) $f ^ { - 1 } ( x ) = \sqrt { \frac { 2 } { x + 4 } } , x \neq - 9$
C) not a one-to-one
D) $f - 1 ( x ) = \sqrt { \frac { x + 9 } { 2 } } , x \geq - 9$