Solve for X in 8(x-2) = -4(x+3): Linear Equation with Brackets

Linear Equations with Distributive Property

Solve for x:

8(x2)=4(x+3) 8(x-2)=-4(x+3)

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Step-by-step video solution

Watch the teacher solve the problem with clear explanations
00:08 Let's find X, together.
00:13 First, open the parentheses carefully. Multiply each term inside, with each factor outside.
00:31 Then, rearrange the equation, so all terms with X are on one side.
00:48 Next, combine any like terms, to simplify the equation.
00:53 Now, isolate X by moving other numbers to the opposite side.
01:03 Let's factor twelve into four, and three.
01:08 Simplify the equation, as much as you can.
01:12 Great work! And that's how we find the solution.

Step-by-step written solution

Follow each step carefully to understand the complete solution
1

Understand the problem

Solve for x:

8(x2)=4(x+3) 8(x-2)=-4(x+3)

2

Step-by-step solution

To open parentheses we will use the formula:

a(x+b)=ax+ab a(x+b)=ax+ab

(8×x)+(8×2)=(4×x)+(4×3) (8\times x)+(8\times-2)=(-4\times x)+(-4\times3)

We multiply accordingly

8x16=4x12 8x-16=-4x-12

In the left section we enter the elements with the X and in the right section those without the X, remember to change the plus and minus signs as appropriate when transferring:

8x+4x=12+16 8x+4x=-12+16

We solve accordingly

12x=4 12x=4

We divide both sections by 12

12x12=412 \frac{12x}{12}=\frac{4}{12}

We reduce and obtainx=412=13 x=\frac{4}{12}=\frac{1}{3}

3

Final Answer

13 \frac{1}{3}

Key Points to Remember

Essential concepts to master this topic
  • Distribution: Multiply each term inside brackets by coefficient outside
  • Technique: Move variables left and constants right: 8x + 4x = 4
  • Check: Substitute 13 \frac{1}{3} into original equation: both sides equal 323 -\frac{32}{3}

Common Mistakes

Avoid these frequent errors
  • Not changing signs when moving terms across equals sign
    Don't just copy 8x - 16 = -4x - 12 to get 8x - 4x = -12 - 16 = wrong answer! When moving terms across the equals sign, you must change their signs. Always flip the sign: +4x becomes -4x, and -16 becomes +16.

Practice Quiz

Test your knowledge with interactive questions

Solve for x:

\( 2(4-x)=8 \)

FAQ

Everything you need to know about this question

Why do I need to distribute first before solving?

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Distribution eliminates the brackets so you can see all terms clearly. Without distributing 8(x-2) properly, you can't collect like terms or move variables to one side.

How do I remember which direction to move terms?

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Use the rule: variables go left, numbers go right. When moving terms, always change their signs. Think of it as 'undoing' the operation.

What if I get a fraction as my answer?

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That's completely normal! Many linear equations have fractional solutions. Just make sure to reduce the fraction to lowest terms like 412=13 \frac{4}{12} = \frac{1}{3} .

How can I check if my fraction answer is correct?

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Substitute your fraction back into the original equation. Both sides should give you the same value. For example: 8(132)=4(13+3) 8(\frac{1}{3}-2) = -4(\frac{1}{3}+3) both equal 323 -\frac{32}{3} .

Why did we collect variables on the left side?

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It's just convention - you can collect them on either side! The key is to pick one side and stick with it. Most people choose left side because we read from left to right.

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