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July 31, 2014

July 31, 2014

Posted by **Rachale** on Wednesday, June 24, 2009 at 5:02pm.

Let f(x) = 6/x-1 and g(x) = 1 + 3/x find the composite function of (fog)(x)

(fog)(x) = f (g(x))

=f (1+3/x)

=6/x-1

????

- Algebra -
**Reiny**, Wednesday, June 24, 2009 at 5:55pmok up to

=f (1+3/x) , then

= 6/[1+3/x - 1]

= 6/(3/x)

= 2x

- Algebra -
**Rachale**, Wednesday, June 24, 2009 at 5:59pmSo 2x would be the answer? I was thinking about including the 1+3/x-1 in the middle of the problem... So then 2x is it then I suppose?

- Algebra -
**Reiny**, Wednesday, June 24, 2009 at 6:04pmIt is a good idea to check you final answer by picking some value of x

e.g let x = 3

g(3) = 1+3/3 = 2

then f(g(3)) = f(2) = 6/(2-1) = 6

my expression was f(g(x)) = 2x

then f(g(3)) = 2(3) = 6

Even though this does not "prove" that I have the right answer, there is a very high probability that it is correct.

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