Inverse f(x)

  • Thread starter luznyr
  • Start date
  • #1
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Homework Statement



Find inverse of f(x) when f(x) = (2x-5)/(7x+4)

Homework Equations



none

The Attempt at a Solution



x=(2y-5)/(7y+4) and then i get stuck trying to rearrange back to y=...
 

Answers and Replies

  • #2
Dick
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Where do you get stuck?? Multiply both sides by 7y+4, move all of the terms with a y in them to one side and solve for y. It's not that hard.
 
  • #3
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ok that gives x(7y+4) -2y= -5, 7xy+4x-2y=-5, so how do i get it back to y= then genius?
 
  • #4
danago
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Keep all your terms with 'y' in them on one side, and all the other terms on the other, and then take out a factor of 'y', and it should be clear from there.
 
  • #5
Dick
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So 4x+5=2y-7xy=y(2-7x). Can you solve for y now, genius?
 
  • #6
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haha yep ty
 
  • #7
Dick
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BTW sorry about the 'it's not that hard' crack. If you don't see it, you don't see it.
 
  • #8
28
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yeah sry bout the genius thing, thanks for the help anyone, much appreciated
 

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