f(x) = sqrt(x+9); g(x) = 8x - 13
Find f(g(x))

Question

f(x) = sqrt(x+9); g(x) = 8x - 13
Find f(g(x))

anonymous · Answer

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

swissgirl · Answer

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

anonymous · Answer

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

swissgirl · Answer

$f(x)= \sqrt{x+9}$
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 }$

anonymous · Answer

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

swissgirl · Answer

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