How to Write a System of Equations in Word

The curly brace wrapping every equation in a system is the hardest thing to draw by hand in Word, stretching a brace character always ends up the wrong size for however many lines you actually have. Word has a dedicated template for exactly this, called Cases.

How to insert a system of equations with the Cases template

1. Open an equation (Alt + =).
2. On the Equation tab, in the Structures group, click Cases (usually right next to Matrix).
3. Pick the template with a left curly brace and however many blank lines you need, or start with a 2-line template and add more later if you're not sure how many equations you'll need.
4. Type each equation into its own line, press Enter or use the add-line button in the corner of the box to create a new line. The brace stretches automatically to match.

Lining up the equals signs

To keep every equation's = sign lined up in a column (which looks far more professional than letting them fall wherever), type the left-hand sides with roughly the same relative length, or use tab alignment right inside the equation box if your Word version supports it. The simplest, most reliable approach is still to type it out and nudge each line by eye until it looks even.

Just need a brace over multiple lines, not a real system?

If you only need a curly brace spanning several lines and it isn't technically a system of equations (a piecewise function definition, for example), the Cases template still works. It's the same underlying structure; Word doesn't care about the math meaning, only the shape: “one brace, several lines inside.”

See also how to write a matrix in Word if you need to present coefficients as a matrix instead of listing each equation individually.