Find the interval where function is increasing or decreasing

Jan 2015
20
2
Philadelphia
So this is supposed to be basic problem. I can't find help anywhere online since they want to show if its increasing or decreasing based on a graph. The problem I'm now doesn't have a graph. It just gives me the function f(x)=3x+5. The derivative is just 3. With this information how do I know if it's increasing or decreasing on either side?
 

skeeter

Math Team
Jul 2011
3,276
1,769
Texas
$f'(x)=3 > 0$ ... what does a derivative that is always positive tell you about the behavior of a function?

If you don't know, I recommend you research the topic more thoroughly.
 
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Jan 2015
20
2
Philadelphia
$f'(x)=3 > 0$ ... what does a derivative that is always positive tell you about the behavior of a function?

If you don't know, I recommend you research the topic more thoroughly.
A derivative that's always positive. Is it far fetched to say that that it can be increasing OR decreasing from either side?