Introduction

Warehouse A holds $10$ chairs, $4$ tables, $6$ lamps. Warehouse B holds $7$ chairs, $5$ tables, $2$ lamps.

Writing that as a grid (a matrix) lets you add deliveries, scale an order, multiply systems, and later describe reflections and rotations.

A matrix is a rectangular array of numbers. You will compute with $2\times 2$ and $3\times 3$ matrices — including determinants written in proper row-and-column form.

You need comfort with basic algebra (substitution, solving simple equations) and careful arithmetic. Every matrix in this course is typeset as a real grid, not a flat list of commas.