Which mapping diagram represents a function from x to y? Hurry please.

Can someone explain the elimination method to me for this problem?

Which function has the same domain as y=2x

1. there are 25 students who started computer programming in elementary school and 25 students who started computer programming in middle school. the first group had a mean final project grade of 95% and the second group had a mean final project grade of 92%. the line plot shows the differences after 10 rerandomizations. determine whether the difference in the means of the two groups is significant based on the line plot. explain your answer.