Solving Equations · One-step equations · 2.3

Divide to solve.

When x is multiplied by a number, divide both sides by it. 4x = 20 → divide by 4 → x = 5.

01 / THE IDEA

See it work.

Watch the method

Divide to solve

4x = 20 → divide both sides by 4 → x = 5.

1 / 2
4x=204x = 20
1

The equation

Solve for x — find the value that makes both sides equal.

4x=204x = 20
2

Divide by the coefficient

Divide both sides by 4 to get x by itself.

x=5x = 5
02 / YOUR TURN

Practice until it feels automatic.

Your turn

Solve for x.

Type the value of x — a number or a fraction like 3/2.

streak 0
best 0
…x =
— / WHY IT WORKS

The idea underneath.

Divide to undo a times

If ax = b, then x = b ÷ a (divide both sides by a).

Why it works

4x = 20 → x is a quarter of 20.

03 / WORKED EXAMPLES

From easy to tricky.

EX 1easy

Solve 4x = 20

1

The equation

Solve for x — find the value that makes both sides equal. 4x = 20

2

Divide by the coefficient

Divide both sides by 4 to get x by itself. x = 5

EX 2medium

Solve 5x = 35

1

The equation

Solve for x — find the value that makes both sides equal. 5x = 35

2

Divide by the coefficient

Divide both sides by 5 to get x by itself. x = 7

EX 3hard

Solve 3x = 6

1

The equation

Solve for x — find the value that makes both sides equal. 3x = 6

2

Divide by the coefficient

Divide both sides by 3 to get x by itself. x = 2

04 / COMMON TRAPS

Where students slip.

Trap

Subtracting the coefficient.

Fix

To undo ×4, divide by 4 — don’t subtract.

Trap

Dividing only one side.

Fix

Divide both sides by the coefficient.

05 / QUIZ

Test yourself.

The Test

12 problems across three tiers. Auto-graded on submit. Hints and a full walkthrough on every question. Your work is saved on this device — sign in to keep it across devices.

0/12Answered
How to answerType just the value. Formatting won't trip you up — we ignore spaces, capital letters, commas, and subscript style, so t₁ = 5, d = 3 and t1=5,d=3 both count. For a list of numbers, separate them with commas (e.g. 3, 10, 17).
Core

Core (4)

C1

Solve 3x = 9

Need a hint?
  • Divide by the number in front of x.
  • Do it to both sides.
C2

Solve 6x = 42

Need a hint?
  • Divide by the number in front of x.
  • Do it to both sides.
C3

Solve 6x = 54

Need a hint?
  • Divide by the number in front of x.
  • Do it to both sides.
C4

Solve 4x = 20

Need a hint?
  • Divide by the number in front of x.
  • Do it to both sides.
Apply

Apply (4)

A1

Solve 6x = 30

Need a hint?
  • Divide by the number in front of x.
  • Do it to both sides.
A2

Solve 2x = 18

Need a hint?
  • Divide by the number in front of x.
  • Do it to both sides.
A3

Solve 6x = 54

Need a hint?
  • Divide by the number in front of x.
  • Do it to both sides.
A4

Solve 5x = 15

Need a hint?
  • Divide by the number in front of x.
  • Do it to both sides.
Extension

Extension (4)

E1

Solve 2x = 4

Need a hint?
  • Divide by the number in front of x.
  • Do it to both sides.
E2

Solve 3x = 27

Need a hint?
  • Divide by the number in front of x.
  • Do it to both sides.
E3

Solve 3x = 27

Need a hint?
  • Divide by the number in front of x.
  • Do it to both sides.
E4

Solve 5x = 35

Need a hint?
  • Divide by the number in front of x.
  • Do it to both sides.