Find f(g(x)) for f(x) = 3x - 1, g(x) = x^2 + 2x - 4

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will7675

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Nov 1, 2006
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I don't know where to start!

If f(x) = 3x-1 and g(x) = x^2 + 2x - 4, find f[g(x)]

So far I know I need to substitute in the sppopriate places, it sounds easy but everytime I go to do it, it is really really hard!

Can someone walk me through this?
Thanks!
 
With a composition, all you do, in this case, is sub g(x) into f(x)

\(\displaystyle f(x)=3x-1\)

\(\displaystyle g(x)=x^{2}+2x-4\)

\(\displaystyle f(g(x))=3(x^{2}+2x-4)-1\)
 
I am taking this class online through the college, so all I get from the instructor or lecture notes which don't help much!
It's easier is someone actually explains the steps to me!
 
will7675 said:
It's easier is someone actually explains the steps to me!
Click to expand...
Okay. Then follow the link in the previous reply to find links to the requested explanations. (It isn't really feasible to provide the missing classroom instruction within this environment, but there are plenty of great resources online.)

Find an explanation from the listing at the link that "works" for you (different people have different tastes, naturally). Then, once you've learned the basic terms and techniques, please attempt the exercise. If you get stuck, please reply showing all of your work and reasoning.

Thank you.

Eliz.
 
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