i just answered one of these i believe the answer is continuous.

now, there are 1000 grams in one Kilogram, so in 1680 grams, there are 1680/1000 Kilograms, namely 1.680.
Answer:
Exact form is 
the decimal form is 5
Step-by-step explanation:
Use the linear slope formula to solve for m:
m=(y2-y1)/(x2-x1)
using the points (-1,1) and (1,5) you can find the slope for the first interval:
m=(5-1)/(1-(-1))
m=4/2
m=2
you can double check by using the same formula on the second interval, which is (1,5) to (3,9).
m=(9-5)/(3-1)
m=4/2
m=2
therefore, the rate of change is 2.
0.0000021 you need to divide 2.1 by 10^6