Posted by Rachale on .
Let f(x) = 6/x1 and g(x) = 1+3/x. Please find the composite function of (fog)(x)

Algebra 
MathMate,
(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/x1
and g(x) = 1+3/x
you would find
(fog)(x)
= f(g(x))
= 6/g(x) 1
= 6/(1+3/x)  1
= (5x3)/(x+3) 
Algebra 
Rachale,
So in other words the final answer would be what? I got 2x. Is this correct?

Algebra 
MathMate,
I got (5x3)/(x+3).
Can you show me how you got 2x? 
Algebra 
MathMate,
Actually, it slipped my memory:
There is probably a misinterpretation of the parentheses:
f(x) = 6/(x1) and g(x) = 1+3/x
so
f º g (x)
=f(g(x))
=f(+3/x)
=6/(1+3/x1)
=6/(3/x)
=2x
If this is the case, the answer is (A).
See:
http://www.jiskha.com/display.cgi?id=1245900271