Answer:

Step-by-step explanation:
To simplify recall exponent rules:
1. An exponent is only a short cut for multiplication. It simplifies how we write the expression.
2. When we multiply terms with the same bases, we add exponents.
3. When we divide terms with the same bases, we subtract exponents.
4. When we have a base to the exponent of 0, it is 1.
5. A negative exponent creates a fraction.
6. When we raise an exponent to an exponent, we multiply exponents.
7. When we have exponents with parenthesis, we apply it to everything in the parenthesis.
We will use these rules to simplify.
Use rule #3 to simplify inside the parenthesis first.

Now simplify the exponent of 4 using rule 6.

Answer:
20,365.7 seconds
Step-by-step explanation:
First, we need to know how to convert yards to miles, as the question is in miles. We know that 1 mile is equivalent to 1760 yards. So we have:
1 mi = 1760 yards
If we multiply both sides by 81:
81 mi = 142,560 yards
And we know that the sprinter needs 8 second to run 56 yards:
8 s = 56 yards
If we divide both sides by 56 we get the time he needs for 1 yard:
8/56 s = 56/56 yards
1/7 s = 1 yard
So, takes him 1/7 seconds to run one yard. At this rate he runs 142,560 yards in:
(1/7) * 142,560 = 20,365.7
So, he needs 20,365.7 seconds to run 81 miles (142,560 yards)
Answer:
D
Step-by-step explanation:
Hey there!
We can condense 18 to 9 times nine. However, 9 isn't prime, so we can break that down to 3 times 3 times two, all of which are prime.
Hopefully this helps!