[ubuntu] Problem with unknown partition

I downloaded Gparted Partition and saw that there was an unknown Partition
When I found out more, I knew that it is the Swap partition, and I have 2 Swap Partition:

fdisk -l

Disk /dev/sda: 320.1 GB, 320072933376 bytes
255 heads, 63 sectors/track, 38913 cylinders, total 625142448 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x6e304e05

Device Boot Start End Blocks Id System
/dev/sda3 2048 385931263 192964608 7 HPFS/NTFS/exFAT
/dev/sda4 467855358 625141759 78643201 5 Extended
/dev/sda5 617144320 625141759 3998720 82 Linux swap / Solaris
/dev/sda6 467855360 613230591 72687616 83 Linux
/dev/sda7 613232640 617136127 1951744 82 Linux swap / Solaris


I do not know if I can delete one of these to have more free space.
Could you guys give me some advices?