Answer:
(9, <u>81</u>) (<u>8</u>, 71)
Step-by-step explanation:
My explanation is in the picture. All I did was replace the known variable with the proper letter!
Answer:
33.3333% decrease
Step-by-step explanation:
Percent change formula:
, where x is the new value and y is the starting value.
Plug in values and solve:

-33.3333% change, or a 33.3333% decrease.
Answer:
5.497787144 miles
Step-by-step explanation:
Remember that circumference of a circle can be calculated with:

r=radius
We also know that the radius is just a half of the diameter.
So, the radius of the track is (1/2)/2=1/4 miles
Now, use the circumference of a circle formula to find how much she runs in 1 lap.

Simplify

This is how much she runs in 1 lap.
Multiply by 3.5 for 3 and a half laps.

The answer is around 5.497787144 miles.
Answer:
14x + 23
Step-by-step explanation:
The lengths of three sides of a triangle are 5x + 9 feet, 2x + 14 feet, and 7x feet.
The perimeter of a triangle: the sum of all of its sides.
5x + 9 + 2x + 14 + 7x
14x + 23
It's the expression of the perimeter of the triangle. Once you will be asked to find x, you'll probably be given the exact perimeter of the triangle.