Assuming n is the number of signers.
7 is 10% of y.
7 = 0.1y
y = 70
n is 80% of y
n = 0.8y
n = 0.8(70)
n = 56
56 signers
x-coordinates for the maximum points in any function f(x) by f'(x) =0 would be x = π/2 and x= 3π/2.
<h3>How to obtain the maximum value of a function?</h3>
To find the maximum of a continuous and twice differentiable function f(x), we can firstly differentiate it with respect to x and equating it to 0 will give us critical points.
we want to find x-coordinates for the maximum points in any function f(x) by f'(x) =0
Given f(x)= 4cos(2x -π)

In general 
from x = 0 to x = 2π :
when k =0 then x = π/2
when k =1 then x= π
when k =2 then x= 3π/2
when k =3 then x=2π
Thus, X-coordinates of maximum points are x = π/2 and x= 3π/2
Learn more about maximum of a function here:
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I believe the green one bc it doesn't go into a point from all angles
Answer:
The value of x is 20.
Step-by-step explanation:
The steps are :
0.75x - 13 = 2
0.75x = 2 + 13
0.75x = 15
x = 15 ÷ 0.75
x = 20