Confusion on a subtraction problem

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In summary, the correct answer for the expression \frac{x}{x^2-9} - \frac{1}{2x-6} is \frac{x}{(x-3)(x+3)}-\frac{1}{2(x-3)} after bringing to a common denominator and simplifying. Daniel made a mistake when subtracting the numerators, but now understands the correct solution.
  • #1
sportsguy3675
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[tex]\frac{x}{x^2-9} - \frac{1}{2x-6}[/tex]

When I first worked this problem I found the answer to be:
[tex]\frac{1}{2x-6}[/tex]

However, in my English class we had this Vietnamese substitute who took my worksheet and did the problems on it in his head and pointed at the answer I wrote for this problem and walked away. He came back and worked it out in front of me and he got the answer:
[tex]\frac{1}{2x+6}[/tex]

Which answer is correct?
 
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  • #2
He is.

[tex] \frac{x}{(x-3)(x+3)}-\frac{1}{2(x-3)} [/tex]

Bring to a common denominator and then simplify.

Daniel.
 
  • #3
Whoops, I see where I went wrong. Messed up when I subtracted the numerators. :( Thanks for the clarification.
 

Related to Confusion on a subtraction problem

1. What is a subtraction problem?

A subtraction problem is a mathematical operation that involves taking away a certain number (the subtrahend) from another number (the minuend) to find the difference or remainder.

2. Why do people get confused with subtraction problems?

People may get confused with subtraction problems because it requires a different way of thinking compared to addition. Subtraction involves working backwards from the total to find the missing number, which can be challenging for some individuals.

3. What are some common mistakes people make when solving a subtraction problem?

Some common mistakes people make when solving a subtraction problem include forgetting to regroup or borrow when necessary, mixing up the order of numbers, or making calculation errors.

4. How can I avoid confusion when solving a subtraction problem?

To avoid confusion when solving a subtraction problem, it is important to understand the concept of subtraction and practice regularly. It can also be helpful to use visual aids, such as a number line or manipulatives, to better understand the problem.

5. Are there any tips for solving subtraction problems more efficiently?

Yes, there are a few tips for solving subtraction problems more efficiently. These include breaking down the problem into smaller parts, using mental math strategies such as subtracting from a multiple of ten, and checking your answer by using addition or estimation.

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