Hey guys im revising for an exam and they have given us some extra revision questions as a challenge however i have no clue on how to do these 3 questions, if anyone can explain them to me or give me a solution so i can understand it would be helpful thanks

http://img176.imageshack.us/img176/9329/mathso.png

i cropped out the 3 questions i don't understand on the above picture, any help is appreciated thanks