# Matrices Exercises

#### Basics

As always, there you are with two equations staring you dead in the face. For example:x + 4y = 6 and2x – 3y = 9Remember that variables are the letters, and coefficients are just the numbers in...

#### Beginning Operations

First, we'll learn how to make a coefficient matrix. We'll start with the following examples:x + 4y = 6 2x – 3y = 9 This is all fine and dandy; we know all about coefficients. The first...

#### Cramer's Rule

Cramer's Rule has nothing to do with Seinfeld, guitars, or horrible movie divorces. It has everything to do with solving systems of equations using our uptight friends, determinants. That's how C...

#### Cramer's Rule Redux

Determinants and Cramer's Rule Redux: Because Things Happen in ThreesHere's the first trick for using Cramer's Rule on 3 × 3 matrices. This does not work for 4 × 4s or larger matrices, and of c...

#### Adding and Subtracting Matrices

Adding, Subtracting, and Matrices, Oh My!It's simple to add and subtract matrices, but they must always be the same size for it to work. The answers are always the same size too. Check it out:All...

#### Scalar Multiplication

Scalar Multiplication: One is the Loneliest Scalar?We can multiply matrices by scalars to produce new matrices, for example, when all of the payoffs in a game are doubled.We know what you're thin...

#### Multiplying Matrices

Multiplying Matrices: Further Down the Rabbit HoleSo far, we've been dealing with operations that were reasonably simple: adding and subtracting matrices is limited to same-sized matrices, and scal...

#### In the Real World

Let's say you're working at A & F in the mall. You're in charge of shirts, because your manager thinks you have real promise. Don't let her down!First, you're doing an inventory of red polo s...