Composite Function Check:
Did i do this correctly?

Given f(x)=x^3-8
g(x)=2x-4

find g(f(2))
This is what i did:
2^3-8=0
then i took the 0 and plugged it into g(x) so
2(0)-4=-4
this made my answer -4. Is that correct? Did i do this right??

Question

Composite Function Check:
Did i do this correctly?

Given f(x)=x^3-8
          g(x)=2x-4

find g(f(2))
This is what i did:
2^3-8=0
then i took the 0 and plugged it into g(x) so
2(0)-4=-4 
this made my answer -4. Is that correct? Did i do this right??

anonymous · Answer

That's correct,  though you could also do it symbolically...it'd be more work for the given problem though

kc_kennylau · Answer

That is correct

anonymous · Answer

ok awesome! More work or not i'll do what i gotta do to make sure i understand it and i'm doing it correctly :) Thanks so much!

anonymous · Answer

yep. It looks alright to me

kc_kennylau · Answer

but I would write the following:
$$\hspace{14pt}g(f(2))\=g(2^3-8)\=g(0)\=2(0)-4\=-4$$

anonymous · Answer

Ok so can anyone check this one for me? Using the same function equations however

g(f(0)) 
which i figured this way

g(f(0))=
g(0^3-8)=
g=-8
2(-8)-4=
-16-4
=-20

anonymous · Answer

That looks fine,   but it wasnt' the question asked originally (Which awas g(f(2))

anonymous · Answer

nope it was a new question, i know i probably should have opened a new question but i didn't wanna seem repetitive