Solve Linear Equation: 2(x-4)+6(x+2)=-18 Step-by-Step

Linear Equations with Mixed Number Solutions

2(x4)+6(x+2)=18 2(x-4)+6(x+2)=-18

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Step-by-step video solution

Watch the teacher solve the problem with clear explanations
00:00 Solve
00:03 Open parentheses properly, multiply by each factor
00:09 Collect terms
00:17 Arrange the equation so that only the unknown X is on one side
00:24 Collect terms
00:27 Isolate X
00:37 Break down the fraction into a whole number and remainder
00:42 And this is the solution to the question

Step-by-step written solution

Follow each step carefully to understand the complete solution
1

Understand the problem

2(x4)+6(x+2)=18 2(x-4)+6(x+2)=-18

2

Step-by-step solution

To solve the problem 2(x4)+6(x+2)=18 2(x-4)+6(x+2)=-18 , we follow these steps:

  • Step 1: Apply the distributive property.

Expand both terms using the distributive property:

2(x4) 2(x-4) expands to 2x8 2x - 8 and 6(x+2) 6(x+2) expands to 6x+12 6x + 12 .

Thus, the equation becomes:

2x8+6x+12=18 2x - 8 + 6x + 12 = -18
  • Step 2: Combine like terms.

Combine 2x 2x and 6x 6x to get 8x 8x , and combine 8-8 and 12 12 to get 4 4.

The equation simplifies to:

8x+4=18 8x + 4 = -18
  • Step 3: Isolate the variable x x .

Subtract 4 4 from both sides to isolate terms with x x :

8x=184 8x = -18 - 4

Simplifying the right side gives:

8x=22 8x = -22
  • Step 4: Solve for x x .

Divide both sides by 8 8 to solve for x x :

x=228 x = \frac{-22}{8}

Simplify 228\frac{-22}{8} to 114-\frac{11}{4}, which is 234-2\frac{3}{4} in mixed number form.

Therefore, the solution to the equation is x=234 x = -2\frac{3}{4} .

3

Final Answer

234 -2\frac{3}{4}

Key Points to Remember

Essential concepts to master this topic
  • Distributive Property: Expand parentheses first before combining like terms
  • Technique: Combine 2x+6x=8x 2x + 6x = 8x and 8+12=4 -8 + 12 = 4
  • Check: Substitute x=234 x = -2\frac{3}{4} back: both sides equal 18 -18

Common Mistakes

Avoid these frequent errors
  • Forgetting to distribute to both terms inside parentheses
    Don't just multiply the first term like 2(x-4) = 2x - 4, ignoring the -4! This gives 2x + 6x + 12 = -18 instead of the correct 2x - 8 + 6x + 12 = -18. Always distribute to every term inside the parentheses.

Practice Quiz

Test your knowledge with interactive questions

\( 5x=1 \)

What is the value of x?

FAQ

Everything you need to know about this question

Why do I need to use the distributive property first?

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The distributive property removes parentheses so you can see all terms clearly. Without it, you can't combine like terms properly and will get stuck!

How do I convert the improper fraction to a mixed number?

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Divide the numerator by the denominator: 228=114 -\frac{22}{8} = -\frac{11}{4} . Since 11 ÷ 4 = 2 remainder 3, this becomes 234 -2\frac{3}{4} .

What if I get confused combining the constant terms?

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Remember: addition and subtraction with integers! 8+12=+4 -8 + 12 = +4 because you have 8 negative and 12 positive, leaving 4 positive.

Can I solve this without using the distributive property?

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No! You must eliminate the parentheses first. There's no way to combine like terms or isolate the variable while the terms are still grouped in parentheses.

How do I know if my final answer is simplified correctly?

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Check if the fraction can be reduced further. 228 \frac{22}{8} reduces to 114 \frac{11}{4} because both 22 and 8 are divisible by 2. Always simplify to lowest terms!

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