Attempt to solve this system using the Gaussian elimination you learned from chapter 1:
What linear algebra is involved in AA HL?
Generally, you'sll see matrix operations in AA HL when it comes to solving 3 equations in a system. Although this doesn'st sound like the linear algebra you expected when you first clicked on this chapter, I promise you, Gaussian elimination becomes interesting when involving more than 2 equations!
A deeper dive into Gaussian elimination
From Chapter 1, you know that there's different forms of an augmented matrix that lets you find solutions to systems involving 2 equations, and those rules almost exactly apply to systems with 3, despite having that 3rd row and an additional variable: