i made 3 same topics in one area. how can i delete them?

2admins.
Hi
i made by mistake 3 same threads. Can you please delete 2 of them?
they re
http://www.blackhatworld.com/blackhat-seo/hire-freelancer/78159-i-willl-buy-google-adwords-vouchers.html

http://www.blackhatworld.com/blackhat-seo/hire-freelancer/78168-i-willl-buy-google-adwords-vouchers.html

and

http://www.blackhatworld.com/blackhat-seo/hire-freelancer/78157-i-willl-buy-google-adwords-vouchers.html

sorry for that

Tape, or .

thanks for info