This is a question by PapaSmurf:

Quote:

2)

Letandf(x) = 9x + k and g(x) = kx + 9.

Find the product of all distinct k such that f(g(x)) = g(f(x)). [Word for word, no typos]

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- May 14th 2011, 11:44 AMtopsquarkComposition of Two Functions
This is a question by PapaSmurf:

Quote:

__2)__

Let*and*f(x) = 9x + k and g(x) = kx + 9.

Find the product of all distinct k such that f(g(x)) = g(f(x)). [Word for word, no typos]

- May 14th 2011, 11:55 AMTheEmptySet
Given that

then

setting them equal and expanding gives

Now just solve for k and multiply the two solutions together. - May 14th 2011, 12:06 PMPapaSmurf
Awesome, thank you :)

But, I don't completely understand what you mean at the end.

Quote:

Now just solve for k and multiply the two solutions together.

but don't understand where to go from there... would that be my answer? - May 14th 2011, 12:26 PMTheEmptySet
In the original problem statement is says find the product all of distinct k.

Well you have the two distinct values of k so find their product so multiply them together.