Which x satisfies an equation?

key notes :

What Does It Mean?

When we are asked “Which x satisfies an equation?”, it means:

Find the value of x that makes the equation true.

For example:
If the equation is 2x + 5 = 15, we need to find the value of x that makes both sides equal.

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Steps to Find the Satisfying x

Understand the equation – Identify what is given.

solate the variable (x) – Use inverse operations (opposite operations) to move numbers away from x.

• Addition ↔ Subtraction
• Multiplication ↔ Division

Solve step-by-step – Perform the same operation on both sides of the equation.

Check your answer – Substitute the value back into the original equation to confirm.

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Examples

Example 1
Equation: x + 7 = 12
Step 1: Subtract 7 from both sides → x = 5
Step 2: Check: 5 + 7 = 12 ✅

Example 2
Equation: 3x = 18
Step 1: Divide both sides by 3 → x = 6
Step 2: Check: 3 × 6 = 18 ✅

Example 3
Equation: 2x – 4 = 10
Step 1: Add 4 to both sides → 2x = 14
Step 2: Divide by 2 → x = 7
Step 3: Check: 2 × 7 – 4 = 14 – 4 = 10 ✅

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Tips to Remember

• Always do the same operation on both sides of the equation.
• Be careful with negative numbers.
• If you get x = 0, it can still be correct.
• Checking your solution avoids silly mistakes.

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Practice Problems

Find the value of x that satisfies each equation:

1. x – 9 = 3
2. 5x = 35
3. 2x + 6 = 14
4. 4x – 10 = 6
5. x/5 = 8

A solution to an equation is a value of a variable that makes the equation true.

Learn with an example

let’s practice!