How to resize the root partition in Kubuntu 14.10?

you can resize your root directory in following steps:

1. back up your data first and always since machines fails and you like your data more than anything
2. have a bootable usb stick with ubuntu on it. i think i have a post about dual booting, you can check that one out on how to create one or a simple search on internet can help you on that.
3. restart your machine and boot from the bootable usb you have.
4. be patient
5. you'll be presented with a window with 2 option : 1- Try ... 2- Install ... (...) means the name of your operating system, in my case is Kubuntu, however the procedure is the same(almost)
6. choose "Try ..." 
7. you'll see the desktop
8. now,  navigate to "System" and execute "KDE Partition Manager". you might have something a bit different in your version, but look for something similar.
9. while inside the partition manager, you need to make some space next to your root partition, either side is fine.
10. then you right click on your root partition and select "Resize/Move".
11. you'll be presented with a window to extend your root partition to the unallocated space that you created in step 9. it can be on left or right side of the root. 
12. and that's it.

Some Notes:

• always back up
• click "Apply" after each change in Partition manager
• you can also use GParted". almost same procedure
• unallocated space must be next to the partition you want to extend. 
• there are some cases which you might need to shrink you "swap" partition or other partition not next to your "root" or the one you want to extend, simple search can help you on that. it's easy.
• you might damage your GRUB in the process. don't panic.
• you need to boot from a live cd or bootable usb and execute some command in shell prompt. here is the link for complete explanation Fix GRUB.

I hope this helps, sorry for not including any images. i just wanted to share my experience.