math
posted by jessica .
solve system by matrices
2x+3yz=8
xyz=2
4x+3y+z=6

Have your reviewed the subject of how to solve systems of equations with determinants? You need to do that. There are plenty of tutorials online on that subject.
You want to use Cramer's Rule.
See http://www.maths.surrey.ac.uk/explore/emmaspages/option1.html
It would require several pages to explain but you need to learn it.