Expand root partition without formatting

I would really like a clear guide to expand my root (/) partition. The screenshot shows my partitions (Windows 7/Ubuntu 14.04 - dual boot) and as you can see /dev/sda3 is my Ubuntu partition. I would like to move the 90 GB unallocated partition up to the root and expand the root. I would appreciate help with the following questions:

1. Can I freely resize the data partition (/dev/sda5) until it has no more unused space?
2. Can I even extend the root without formatting it?
3. Can I unmount (so that i may move the 90 GB up) the home partition without bad stuff happening?

My partions:

Thank you very much in advance! Semester begins soon and I have like 10 GB of courseware to fit into the root dir.

1. No
2. Yes
3. Yes

All the above answers are only true if you've booted from the GParted Live CD or the Live Ubuntu CD (with which you've installed Ubuntu)