Posted by **Rachale** on Sunday, June 28, 2009 at 12:16pm.

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

- Algebra -
**MathMate**, Sunday, June 28, 2009 at 12:25pm
(fog)(x) is a notation for substituting g(x) for x in the definition of f(x), in other words,

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

Using f(x) = 6/x-1

and g(x) = 1+3/x

you would find

(fog)(x)

= f(g(x))

= 6/g(x) -1

= 6/(1+3/x) - 1

= (5x-3)/(x+3)

- Algebra -
**Rachale**, Sunday, June 28, 2009 at 12:28pm
So in other words the final answer would be what? I got 2x. Is this correct?

- Algebra -
**MathMate**, Sunday, June 28, 2009 at 2:14pm
I got (5x-3)/(x+3).

Can you show me how you got 2x?

- Algebra -
**MathMate**, Sunday, June 28, 2009 at 2:28pm
Actually, it slipped my memory:

There is probably a mis-interpretation of the parentheses:

f(x) = 6/**(x-1)** and g(x) = 1+3/x

so

f º g (x)

=f(g(x))

=f(+3/x)

=6/(1+3/x-1)

=6/(3/x)

=2x

If this is the case, the answer is (A).

See:

http://www.jiskha.com/display.cgi?id=1245900271

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