With solving systems with three variables, will medal
-2x + 2y +3z = 0
-2x - y + z = -3
2x + 3y + 3z = 5
i'm not sure how to work it out, i have to do it by elimination

The school board administered a math test to all students in grade 66 at high achievers charter school and determined that 15\%15% of them were below grade level in math. based on this data, which of the following conclusions are valid? choose 1 choose 1