To measure the exact quantity of things ;)
Answer:

Step-by-step explanation:

It took about 0.66 hour, which is basically 40 minutes.
Answer:
c
Step-by-step explanation:
The answer is A,

. This is because when plugging in -2 for x, the expression will look like this:

. To make the exponent positive, you have to flip it into a fraction. Then it will be

. Lastly, you simplify the denominator into 81.