You mount file systems, not partitions. Sometimes a partition contains a file system and it appears that you "mount a partition" even if that's not exactly the case.
Extended partition is just a container for logical partitions, it doesn't contain a filesystem that could be mounted. LVM partitions are physical volumes for the Logical Volume Management system and they don't have filesystems directly on them. You must find the LVM Logical Volumes that contain mountable filesystems.