Find Inverse of Function: Homework Help

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To find the inverse of the function f(x) = (x + 2)/(3x + 5), start by switching y and x, leading to the equation x = (y + 2)/(3y + 5). The next step involves distributing y on the right side and rearranging the equation to isolate y. This requires moving all y terms to one side and factoring out y, followed by dividing to solve for y. The discussion emphasizes the importance of careful algebraic manipulation to avoid confusion and achieve the correct inverse function.
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Homework Statement


I need to pass a test to get into college calculus, but there's a few things I've forgotten since may, one of them being how to find the inverse of a function with x in the denominator. I think I remember it being something really simple that I'm overlooking, but here it goes:

Homework Equations


f(x) = (x + 2)/(3x + 5)

1) y = (x + 2)/(3x + 5)
2) x = (y + 2)/(3y + 5)
3) this is where it starts to go crazy.

The Attempt at a Solution


My attempts were kind of convulsive, but I hope it'll suffice to say that I know to switch y with x, then solve the problem for y, which will be the inverse. I just don't know how to get y out of the denominator without getting a really complicated answer. (edit: I put what I was saying into math form above)

Thanks, if anyone knows this. I've done some re-learning in the past week or so; there are just a few things left that are too specific to find online.
 
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Your goal is to use properties of equality of real numbers to find a formula for y. Either you can find a result or you cannot. Can you obtain an inverse in that general manner?
In fact, a result is possible; whether the result is a function, I leave for you to decide.
 
If the y=\frac{x + 2}{3x + 5} then x+2=y(3x+5). Your goal is to present x in terms of y. Now can you proceed?
 
Дьявол said:
If the y=\frac{x + 2}{3x + 5} then x+2=y(3x+5). Your goal is to present x in terms of y. Now can you proceed?

That's where I get, but I can't go further without jumbling the whole thing up.
 
GHealy said:
That's where I get, but I can't go further without jumbling the whole thing up.

Distribute the y on the right hand side, separate y and non-y terms to opposite sides, factor out y and divide.

--Elucidus
 
Elucidus said:
Distribute the y on the right hand side, separate y and non-y terms to opposite sides, factor out y and divide.

--Elucidus

*facepalm*

I can't believe I forgot simple algebra. Thanks.
 
What I did was, multiply the numerator and then expand everything. Bring all the x-terms and the xy-terms to one side, and the y-terms and constants to the other. Then I factored out x, and divided by the other stuff!
Good luck =)
 
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