Let f(x) = (x2 + 3x – 4) and g(x) = (x + 4).

Question

kainui · Answer

I'll let them.

anonymous · Answer

so??

hba · Answer

You have to find f(g(x)= 


Right ?

anonymous · Answer

yes but how do you do that?

hba · Answer

You just plug in 

g(x) which is x+4

in


f(x)= (x2 + 3x – 4)

f(g(x))=f(x+4)=

Just put x+4 in place of x


got it ?

anonymous · Answer

not really...

hba · Answer

f(g(x)=f(x+4)=[(x+4)^2+3(x+4)-4]

Now solve it more.

hero · Answer

Don't tell me you're still working on it. Did you figure it out yet @mathhelp9 ?

anonymous · Answer

sorry hero. it was very late i had to sleep. thanks for your help. i think i got it!

hba · Answer

Ok good :)

hero · Answer

If you figured it out, you're supposed to post what you got just in case you made a mistake so that we can confirm your correct answer.

anonymous · Answer

i was totally off track. i couldn't finish it.

hba · Answer

Show us your working....

f(g(x)=f(x+4)=[(x+4)^2+3(x+4)-4]

anonymous · Answer

Ok. This is what I got. Pls verify if this is right. thx for your helo.

f(x) • g(x) = f(g(x)) 

f(x+4) = (x+4)^2 + 3 (x+4)-4

f(x+4)=x^2+11x+24

If x is positive: 

(x+3)(x+8)=f(x+4)