(Click Here) Why should game developers use OpenGL instead of DirectX

Most of you must have heard about DirectX, whenever you install a PC game it usually asks also to install its own DirectX files. If they aren't installed correctly you usually get error sayin d3dx9__.dll/d3dx10__.dll etc. not found.
Actually both OpenGL and DirectX are the standards for development for games.
They are used by the games to interact with the hardware components etc. to run on the machine,that is why often while installing games you are prompted to install DirectX components so that those games can interact with your machine, also many times Visual C++ runtime components are also installed because developers mostly use Visual C++ as the preferred option for DirectX coding.
DirectX is used by the Microsoft Windows and Xbox series, while OpenGL is cross-platform based and can be used by Mac, various versions of Linux unlike the former one .
OpenGL actually stands for Open Graphics Library and was open source.
On the other hand DirectX stands for "Direct3D, DirectInput and DirectSound" and was developed by Microsoft Corp. to encourage game developers to use windows first choice( and so far it has succeded by its extensive marketing campaign). So, do checkout the above link.