## keeponbleeding 2 years ago f(x) = sqrt(x+9); g(x) = 8x - 13 Find f(g(x))

1. keeponbleeding

Am I putting the g(x) in f(x) or vice versa? I know how to solve afterwards

2. swissgirl

Your g(x) becomes then new x value f(8x-13)

3. keeponbleeding

f(g(x))= 8sqrtx-4?

4. swissgirl

$$f(x)= \sqrt{x+9}$$ Now since its f(g(x)) That is another way of saying f(8x-13). Meaning we replace our x with 8x-13 $$f(8x-13)= \sqrt{(8x-13)+9 }$$ Now we have to simplify by opening the brackets $$f(8x-13)= \sqrt{(8x-4) }$$ $$f(8x-13)= \sqrt{4(2x-1) }$$ $$f(8x-13)= 2\sqrt{2x-1 }$$

5. keeponbleeding

oh ok I think I got it, Im going to try it on my last problem now. thanks so mucH!

6. swissgirl

No problem. You can always just come back here and check if you got your answer correct :)