i need to remove blekko from safari

Go to Safari menu (At the very top right side of your screen next to Apple icon), choose "Quit Safari"

press "Shift" button and while holding this button on your keyboard single click on the Safari icon on your Dock.

Open Safari - Preferences - Privacy - Remove All Website Data.

Apart from that, run Adwaremedic. It is a tiny tool, which will remove the adware within several seconds. You can download Adwaremedic from this website: http://www.adwaremedic.com/index.php

You can also remove the adware manually using the steps provided by Apple: https://support.apple.com/en-us/HT203987

Also, I believe it would be a good idea to install AdBlock.

Safari/Preferences/Search and set a new search engine.

Are you using "Glims" or some other third-party software that modifies Safari?