This system



becomes



You didn't say to solve it, but I will anyway, because no doubt
you'll be given some later to solve, and you can use this as a
model to go by:

To solve it find the inverse of the coefficient matrix, which is



Then left-multiply both sides of the matrix equation by this inverse:



Multiply the first two matrices on the left, and multiply the
matrices on the right:



Multiplying the matrices on the left (the one on the left is the identity
matrix)



So the solution is x=2, y=1, z=-1.

Edwin