Solve one-step equations

Key Notes:

What is a One-Step Equation?

A one-step equation is an equation that can be solved in just one operation (addition, subtraction, multiplication, or division).

Example: x+5=12

Here, you can solve for x by performing just one operation.

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Key Rule: Balance

An equation is like a balance scale — both sides must stay equal.
Whatever you do to one side, you must do to the other side.

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Steps to Solve One-Step Equations

Case 1: Addition

If the equation is x + a = b

• Do the opposite (subtract a from both sides).

Example: x+7=15

x=15−7

x=8

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Case 2: Subtraction

If the equation is x – a = b

• Do the opposite (add a to both sides).

Example:

x−4=10

x=10+4

x=14

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Case 3: Multiplication

If the equation is a·x = b

• Do the opposite (divide both sides by a).

Example: 3x=183

x = 183

x=18

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Case 4: Division

Example: x/6=12

Step 1: Multiply both sides by 6. x=12×6

Answer: x=72

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Special Case: Negative Numbers

Follow the same rules, but be careful with signs.

Example: x−(−3)=7

This means: x+3=7

x=4

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Check Your Answer

Always substitute your answer back into the original equation to verify.

Example:
Equation: x+7=15
Solution: x=8
Check: 8+7=15 ✅

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Practice Problems

Solve for xxx:

• x+12=20
• x−9=5
• 4x=24
• x7=3
• x+(−5)=−1

Learn with an example

let’s practice!