The values of the variables are as follows:

• $x = 2$
• $y = 2$
• $z = 1$
• $a = 5$

Would you like a detailed explanation of how these values were derived or have any further questions?

Here are 5 related questions to further explore the topic:

1. How do we solve a system of equations using matrices?
2. What is the significance of the identity matrix in matrix equations?
3. How can matrix operations be applied to solve linear equations?
4. What are some real-world applications of solving systems of linear equations using matrices?
5. How does matrix multiplication differ from scalar multiplication?

Tip: When solving matrices, it's essential to align each element in corresponding positions to create equations for unknowns.