# Finals revew of functions

#### thisishard

I have my math finals next week and i still don't understand how to even start to do functions. These aren't even 1/4 of the problems on my review sheet. These are just the ones I don't remember how to start(Worried) Can some one please help me through these?

Find g[h(x)] and h[g(x)]
"I was able to do all 10 questions but these 2"
g(x)=x+4
h(x)=x+9

g(x)=|x|
h(x)= x-3

if f(x) =x^2, g(x)=3x, and h(x) = x-1 find each of the following
g[f(x)]

[f o h](3)

Find the inverse of each function
f(x)=3x-4 "is the answer f(x^-1)=(x-6)/3"

g(x)= (-3x+1)/2

h(x) = 4x^2 +12x + 9

Are the following functions inverses
"I don't even know what to do here"
f(x) = (2x-8)/2

g(x) = x +4

#### pickslides

MHF Helper
There are a lot of quesitons here, did you make some attempts? if so you should post them

Find g[h(x)] and h[g(x)]
"I was able to do all 10 questions but these 2"
g(x)=x+4
h(x)=x+9
$$\displaystyle g[h(x)] = (x+9)+4=\dots$$

$$\displaystyle h[g(x)] = (x+4)+9=\dots$$

if f(x) =x^2, g(x)=3x, and h(x) = x-1 find each of the following
g[f(x)]

[f o h](3)
$$\displaystyle g[f(x)] = 3(x^2)$$

$$\displaystyle [f \circ h](3) = (3-1)^2$$

Find the inverse of each function
f(x)=3x-4 "is the answer f(x^-1)=(x-6)/3"
Nope

$$\displaystyle x=3y-4$$

$$\displaystyle x+4=3y$$

$$\displaystyle \frac{x+4}{3}=y$$

$$\displaystyle f^{-1}x=\frac{x+4}{3}$$

Are my answers correct?