Question

f(x)=x^2-f and g(x)= 2x+1
Find f(g(x))
help!

Answer 1

\[f(x)=x^2-4 \]

Answer 2

\[g(x)=2x+1\]

Answer 3

Well ill try this:
\[f(g(x))=f(2x+1)=(2x+1)^2-4=4x^2+4x+1-4=4x^2+4x-3\]

Answer 4

Woah... What?

Answer 5

I think I understand where you got the f(2x+1)? But I'm not sure...

Answer 6

Basically when you say \(f(g(x))\), your referring to the operation of wherever x was in f(x), your putting \(g(x)\) instead!

Answer 7

So you would have
\[f(g(x))=f(2x+1)=(2x+1)^2-4\] Because before, \(f(x)=x^2-4\) But now im putting g(x) where x was.

Answer 8

Okay, I see that. Now what for the next problem it wants me to find 2f(3)+3g(-2) I don't get it.

Answer 9

OOOOH Ouch that's okay. So:
\[\eqalign{
&f(x)=x^2-4 \\
&g(x)=2x+1 \\
}\]
Still right?

Answer 10

Yes,

Answer 11

Would I just put 3 in for f(x) then it would make: \[2=3^2-4\]