Have you tried to find out what directories you have there?
Work your way down (or up) and see what you can see - what is there? What is missing?eg
cd /opt/rh/rh-mysql57/root/usr/
cd /opt/rh/rh-mysql57/root/
cd /opt/rh/rh-mysql57/
cd /opt/rh/
or
ll /opt/rh/rh-mysql57
ll /opt/rh/
or use mc to browse about....
Or say:
cd /opt/rh
find -iname mysqld
A little bit of thought and looking may give you some answers rather than blindly following what others paste.
(people make typos etc, so always worth having a look around)