$$If\ 9-x^2\ge0,$$
Which of the following describes all possible values of x?
$$A.\ 3\ge x\ge-3$$
$$B.\ x\ge3\ or\ x\le-3$$
$$C.\ 3\ge x\ge0$$
$$D.\ -3\le x$$
$$E.\ 3\le x$$
The OA is A.
I don't have clear this PS question but I think that this is a simple question that I can solve the following way,
$$9-x^2\ can\ be\ write\ like\ \left(3-x\right)^2,\ right?$$
$$Then,\ \left(3-x\right)^2\ge0\ is\ equivalent\ to\ \left(3-x\right)\left(3+x\right)\ge0$$
Finally, this expression will be true for,
$$x\ge-3\ and\ x\le3$$
Or
$$-3\le x\le3$$
I appreciate if any expert explains it to me. Thank you so much.
Which of the following describes all possible values of x?
$$A.\ 3\ge x\ge-3$$
$$B.\ x\ge3\ or\ x\le-3$$
$$C.\ 3\ge x\ge0$$
$$D.\ -3\le x$$
$$E.\ 3\le x$$
The OA is A.
I don't have clear this PS question but I think that this is a simple question that I can solve the following way,
$$9-x^2\ can\ be\ write\ like\ \left(3-x\right)^2,\ right?$$
$$Then,\ \left(3-x\right)^2\ge0\ is\ equivalent\ to\ \left(3-x\right)\left(3+x\right)\ge0$$
Finally, this expression will be true for,
$$x\ge-3\ and\ x\le3$$
Or
$$-3\le x\le3$$
I appreciate if any expert explains it to me. Thank you so much.
