Algebra · Equations

Multi-Step Equations

Some equations aren't ready for the two-step dance right away — there's a knot to untangle first. Distribute or combine like terms, and it becomes an equation you already know how to solve.

Part 01

One More Move First

Look at this equation:

3(x + 4) = 21

This isn't a two-step equation yet — the x is stuck inside parentheses. Before we can undo any operation, we need to simplify one side first. Once it's simplified, it turns into an equation you already know how to solve.

Part 02

Simplify, Then Solve

There are two ways an equation might need simplifying before it's ready:

💡 Two Ways to Simplify

Distribute — when a number sits right outside parentheses, like 3(x + 4), spread it across both terms inside: 3x + 12.

Combine like terms — when the variable shows up more than once on the same side, like 2x + 3x, add the matching terms together: 5x.

Once the equation is simplified, it's a two-step equation — undo addition/subtraction first, then multiplication/division. Watch it happen with 3(x + 4) = 21:

1

Distribute the 3

3(x + 4)=21 3x + 12=21
2

Undo the + 12 (subtract 12 from both sides)

3x + 12 − 12=21 − 12 3x=9
3

Undo the × 3 (divide both sides by 3)

3x3=93 x=3
4

Check it

3(3 + 4)=3(7) =21
Part 03

Track the Steps

Your turn to guide the solve. Every equation here needs a simplify step first — watch for whether it's asking you to distribute or combine like terms — then finish it off just like a two-step equation.

Interactive · Multi-Step Solver
Part 04

Why Simplify First?

It's tempting to jump straight to subtracting or dividing — but watch what happens to 3(x + 4) = 21 if you skip the simplify step:

Skip simplify 😖
3(x + 4) = 21
x + 4 = 7 ?
…can't divide just one term
Simplify first 😀
3x + 12 = 21
3x = 9
x = 3

You can't divide only part of one side by 3 — the whole side has to be treated together. Distributing (or combining like terms) first turns a tangled equation into a clean two-step one.

Your Turn!

Practice & Earn Your Score

Solve each multi-step equation. Fill in the line after you simplify, the line after you undo addition/subtraction, then the final value. Press Check — you earn a point when all three blanks are right on the first try.

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Nice work!

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