On linux, one wouldn't normally need to decompress a zip file, so finding the unzip util isn't that high on the list of priorities. But you should be able to just go to the file in whatever directory and type unzip whatever_file.zip
I'm really tired and i'm falling asleep at the keyboard, this could be hazardous to ones health, sorry if it's somewhat odd sounding, but you'll know why...
I don't know if unzip is installed by default or not though in RedHat 7.2, so if you don't have the command, you can install it from the RH cdroms.