Can PS3 games play on the PS1?

Answer 1

A PS3 game cannot play on the PSone. However, a PSone game should be playable on the PS3.
No not on a PS1 or a PS2, PSP or PSP GO. Not on Xbox 360 or Nintendo Wii. The game says PS3 on it because it will work only on the PS3.

Answer 2

YES! EVERY PS3 model is capable of playing original PSX games. As far as PS2 games, only some models are capable of playing those. Your manual will let you know if this is possible.