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

Answer:
2π/7
Step-by-step explanation:
A cosine wave is:
y = A cos(2π/T x + B) + C
where A is the amplitude,
T is the period,
B is the horizontal shift,
and C is the vertical shift.
In this case:
7 = 2π/T
T = 2π/7
X=-1 y=-1, x=1 y=5, x=3 y=11