Confusion on a subtraction problem

  • #1
[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?
 

Answers and Replies

  • #2
dextercioby
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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.
 

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