I need some help with preparing for my Pre-Calculus final

[Littledude]

Since a good amount of you guys probably know how to do this and I know you'd respond pretty quick I thought I'd come here rather than some math forum.
I need to remember some stuff we learned earlier in class that I don't remember and the teacher took all our textbooks today (which was really upsetting since I need it to study).

I need to figure out of to do this problem.
If f(x) = 3x and g(x) = 1/2x , find the following

a) f(g(x))                       b) g(f(x))


thanks

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[dkamm65]

f(x)

<3

[Syntho]

Divide by zero

[Mr. Bill]

  +   =  

On-Topic: I'm not very good at math :c

[Littledude]

+  = 

On-Topic: I'm not very good at math :c

I wouldn't be to surprised if that equation was on my test because the first question in the review packet my teacher gave us is a question that asks what graph does not represent a function and one of the choices was a smiley face.
It looked something like this:

I hope that question is on the final.

[specs112]

I need to figure out of to do this problem.
If f(x) = 3x and g(x) = 1/2x , find the following

a) f(g(x))                       b) g(f(x))


thanks

Composite functions. Substitute an entire function as a variable.

f(g(x)) means that g(x) is treated as the variable, so you do this:

f(g(x)) = f(1/2x) = 3(1/2x), and then you simplify that.

Similarly, g(f(x)) in this case is g(3x) = 1/2(3x), etc.

You put the inside function as the variable in the outside function, then simplify what that gives.