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# Functions watch

1. I have done part a) but not sure if I am thinking of the right idea in part b). I found that f^-1(x) was (-3x)/(x-1) and am I right in thinking that you must insert f^-1(x) as x into f(x)? If so then there is a difficult to fraction to solve which any help with would be great:
(-3x)/(x-1)/((-3x)/(x-1)+3).
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2. (Original post by gs--xa)
I have done part a) but not sure if I am thinking of the right idea in part b). I found that f^-1(x) was (-3x)/(x-1) and am I right in thinking that you must insert f^-1(x) as x into f(x)? If so then there is a difficult to fraction to solve which any help with would be great:
(-3x)/(x-1)/((-3x)/(x-1)+3).
Correct thinking.

from multiplying the overall fraction by x-1 on top and bottom.

Now simplify the denominator.
3. (Original post by RDKGames)
Correct thinking.

from multiplying the overall fraction by x-1 on top and bottom.

Now simplify the denominator.
Ok thanks I get it now I wasn't aware you could do that

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