I have to solve all those with Newton’s binomial, help me pls

Which is an equation for the nth terms of the sequence 12,15,18,21

Jack has a piece of red ribbon that is two times as long as his piece of blue ribbon. he says that he can use two different equation to find out how long his piece of red ribbon is compared to his piece of blue ribbon is. is he correct? explain his reasoning

Suppose i pick a jelly bean at random from a box containing one red and eleven blue ones. i record the color and put the jelly bean back in the box. if i do this three times, what is the probability of getting a blue jelly bean each time? (round your answer to three decimal places.)