Answer:
The expression for two times the difference of 4 and a number is

Step-by-step explanation:
To Find:
Write an expression for Eight times the difference of 4 and a number.
Solution:
Let the Unknown number be 'd'
Difference of 4 and d = ( 4 - d )
So One Time Difference of 4 and d = 1× ( 4 - d )
∴ Two Times Difference of 4 and d = 2× ( 4 - d )
∴ Eight Times Difference of 4 and d = 8× ( 4 - d )
The expression for Eight times the difference of 4 and d. will be

The expression for Eight times the difference of 4 and a number is

Kelly's sister is x years old.
Kelly is 3 years younger than her sister, so Kelly is x - 3 years old.
The sum of their ages is x + x - 3 = 2x - 3.
The sum of their ages is 34, so
2x - 3 = 34
2x = 37
x = 18.5 Kelly's sister's age.
x - 3 = 18.5 - 3 = 15.5 Kelly's age.
Kelly's sister is 18.5 years old.
Kelly is 15.5 years old.
BC= 12
EC= 13
AC= 30
FE= 17
Not really sure if the last two are correct but I hope this helps you
Answer: rate is a ratio that is used to compare different kinds of quantities. A unit rate describes how many units of the first type of quantity corresponds to one unit of the second type of quantity.