Can someone help me ?

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

Given the box plot, will the mean or the median provide a better description of the center? box plot with min at 10.5, q1 at 11.5, median at 12.5, q3 at 13.5, max at 15

Math it's appreciated. (picture provided)