Given: The expression below

To Determine: The matching expression to the given expressions
Solution
Let us simplify each of the expressions using exponents rule

Applying the exponent rule 1 above to the given expressions


Applying the exponent rule 2


Let us not apply exponent rule 1 above


Hence, the matching is as shown below
18/2 = 9 Miles per hour for running
60/3 = 20 Miles per hour for biking
Answer:
We need to add the expression: 
Step-by-step explanation:
As the first step, add the first two polynomials listed in order to find what their sum is. Do such by combining like terms:

now, you need to find another polynomial (let's call it P(x)) such that added to the one we just found above, will render
as a result.
Putting this phrase in mathematical terms, we write:

Now we solve for this unknown P(x) in this equation, by subtracting each of the terms that are accompanying it on the left side of the equation. We do one at a time for clarity:

Therefore, the expression we need to add is: 
The answers are b and c. Plug in -4 for x and solve each option
2(-4) -8 = 0. 0 does not equal 1
3(-4) +8 = -4
1/2 * -4 + 3 = 1, -4+5 = 1
2(1- -4) = 10, -4 + 2 = -2
Answer:
The minimum average speed needed in the second half is 270 km/hr
Step-by-step explanation
We can divide the track in two parts. For the first half of the track the average speed the car achieved was 230 km/hr and we need to make sure that the average speed of the full track is 250 km/hr. Then, we can calculate the average speed of the two parts of the track and force this to be equal to 250 km/hr. In equation, defining
as the average speed of the second half:

Solving for 

Therefore, achieving a speed of 270 km/hr in the second half would be enough to achieve an average speed of 250 on the track.