If f(x)= 3x+2 and g(x)= 4x, then
f(x)+g(x) = 3x+2+4x
= 7x+2
For f(g(x)), you work from the inside and work your way out. Another way of thinking is to go from right to left. (Inside/out and right/left are the same simply using different wording).
So what is g(x)? 4x.
Now, you take 4x and plug it into the f(x).
** Math--> English translation:
Look at the f(x) equation. Wherever you see an x in the f(x), replace the x with 4x [because 4x is the g(x)]. Basically, plug the g(x) into f(x).
So:
f(g(x)) becomes
f(4x) becomes
3 (4x)+2 = 12x+2
** Disclaimer: Notation may be inaccurate.
That's your answer. (Usually you leave it as so, but if your instructor wants it factored, then proceed).
As for the third part, I am unsure of a clear answer, so I am unable to provide an answer at the time.
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Hope that helped.
DISCLAIMER:
Always double check with a reliable source, as mistakes are a possibility. Never use this, or any, platform to cheat.