Solve for X in the Linear Equation: 7 - x = 15 - 5

Linear Equations with Simplification Steps

Solve for X:

7x=155 7 - x = 15 - 5

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1

Understand the problem

Solve for X:

7x=155 7 - x = 15 - 5

2

Step-by-step solution

First, simplify the right side of the equation:
155=10 15 - 5 = 10
Hence, the equation becomes 7x=10 7 - x = 10 .
Subtract 7 from both sides to isolate x x :
7x7=107 7 - x - 7 = 10 - 7
This simplifies to:
x=3 -x=3
Divide by -1 to solve forx x :
x=3 x=-3
Therefore, the solution is x=3 x=-3 .

3

Final Answer

-3

Key Points to Remember

Essential concepts to master this topic
  • Simplify first: Always combine like terms on each side before isolating variables
  • Technique: Subtract 7 from both sides: x=3 -x = 3
  • Check: Substitute x=3 x = -3 back: 7(3)=10 7 - (-3) = 10

Common Mistakes

Avoid these frequent errors
  • Forgetting to simplify before solving
    Don't jump straight to isolating x without simplifying 15 - 5 = 10 first! This creates unnecessary confusion and makes the problem harder than it needs to be. Always simplify both sides completely before applying inverse operations.

Practice Quiz

Test your knowledge with interactive questions

\( x+7=14 \)

\( x=\text{?} \)

FAQ

Everything you need to know about this question

Why do I need to simplify 15 - 5 first?

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Simplifying first makes the equation cleaner and easier to work with! 7x=10 7 - x = 10 is much clearer than 7x=155 7 - x = 15 - 5 .

What does 'isolate the variable' actually mean?

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Isolating means getting x by itself on one side of the equation. You use inverse operations to 'undo' what's being done to x until it stands alone.

Why is the answer negative?

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When we get x=3 -x = 3 , we have negative x equals 3. To find x, we divide both sides by -1, giving us x=3 x = -3 .

How do I check if x = -3 is correct?

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Substitute back into the original equation: 7(3)=155 7 - (-3) = 15 - 5 . This gives us 7+3=10 7 + 3 = 10 , so 10=10 10 = 10

What if I accidentally add 7 instead of subtracting?

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Adding 7 to both sides would give you 14x=17 14 - x = 17 , making the problem more complicated! Always use the opposite operation to cancel out terms.

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