earlier i was messing around with my hard drive in an attempt to make it into a dual boot and in the process using diskutil in terminal i resized my main harddrive but now i would like to make it back to one partition. the diskutil list is this but it wont allow me to delete disk0s3, if anybody can tell me how to restore the 13.7 GB to my mac HD it would be very much appreciated.

andrew-werners-computer-2:/Users/Andrew root# diskutil list
#: type name size identifier
0: GUID_partition_scheme *74.5 GB disk0
1: EFI 200.0 MB disk0s1
2: Apple_HFS Macintosh HD 60.0 GB disk0s2
3: EFI 13.7 GB disk0s3
andrew-werners-computer-2:/Users/Andrew root#