Help please and thank you

Use the elimination method to find the solution to the system of equations. 2x - 3y = -9 -x + 3y = 6

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.

Which inequality has a dashed boundary line when graphed ?