Which is a better buy 5 for $1.00 or 12 for $3: 00 i really need asap

Which function is represented by the graph

Which of the following is true for the relation f(x)=2x^2+1

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