Question about this linear equation with fractions

Click For Summary
The discussion revolves around solving a linear equation involving fractions, where the initial calculation led to an incorrect value for x. The user initially used 2x - 4 as the least common denominator (LCD) but made errors in manipulating the equation. After identifying mistakes in the distribution of terms, the correct simplification revealed that the left-hand side equals 42 - 13x. Ultimately, the correct solution for x is determined to be 3, emphasizing the importance of careful notation and sign accuracy in equations. The conversation highlights the common pitfalls in algebraic manipulation and the need for diligence in calculations.
hackedagainanda
Messages
52
Reaction score
11
Homework Statement
8/(x - 2) - (13/2) = 3/(2x - 4)
Relevant Equations
None.
I use 2x -4 as the LCD and turn 8/(x - 2) - (13/2) = 3 into 16 - 13x - 4 = 3, I then get 12 - 13x = 3 which leads me to 13x = -9 so x = -9/13 which is the wrong answer.

Where did I make a mistake?
 
Physics news on Phys.org
I found my mistake, (-13/2) * 2x -4 is - 13(x - 2) = 13x + 26 so then its 16 + 26 = 42 + 13x = 3 and then 42 - 3 = 39 then 13x = 39 so x is 3.
 
hackedagainanda said:
I found my mistake, (-13/2) * 2x -4 is - 13(x - 2) = 13x + 26 so then its 16 + 26 = 42 + 13x = 3 and then 42 - 3 = 39 then 13x = 39 so x is 3.
The solution may be x = 3, but you have several errors.

−13(x − 2) = −13x +26 .

That gives the Left Hand Side as being:
(2x − 4)(8/(x − 2) − (13/2)) which is 16 + 26 − 13x and finally 42 − 13x

The Right Hand Side becomes 3.
 
Thanks for the tip, I was sloppy when writing down the equation. I need to slow down and make sure all the signs are correct.
 
  • Like
Likes berkeman

Similar threads

  • · Replies 1 ·
Replies
1
Views
1K
Replies
4
Views
2K
  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 21 ·
Replies
21
Views
1K
  • · Replies 21 ·
Replies
21
Views
2K
  • · Replies 10 ·
Replies
10
Views
2K
Replies
2
Views
1K
  • · Replies 39 ·
2
Replies
39
Views
4K
Replies
4
Views
3K
Replies
5
Views
3K