Answer:

Step-by-step explanation:
Answer:
6
Step-by-step explanation:
The circumference of a circle is 
, so
. We can use this because the area of a circle is
. Thus,
.
Step-by-step explanation:
Inflection points are where a function changes concavity (the second derivative changes signs). At x = 4, f"(x) goes from negative to positive, so that's an inflection point. However, at x = 8, we don't know if f"(x) changes signs or not. So we can't say that that's an inflection point.
Answer:
They're not parallel, because 4x and 12x are not the same slope
Answer:
the answer is the last one
Step-by-step explanation: