Help With Electronics Technology

[Pudd]

So, I've been studying with past exam papers and using the answering scheme to help me when I don't understand what to do. I'll look up the method to get the answer, and then do the question myself, making notes.
But I got to a question on operational amplifiers which I really didn't understand. Please help me.

Question
http://i609.photobucket.com/albums/tt172/Pudd100/Work/TSq.jpg

Answer
http://i609.photobucket.com/albums/tt172/Pudd100/Work/TShelp.jpg

[Pudd]

Never mind. Exam over, probably failed :/

[Magus]

Never mind. Exam over, probably failed :/
Oh, sorry man. :( I would have helped you, but I myself failed in applied physics.

Goddamn cyclotron!

[Pudd]

I passed physics last year, god knows how lol.