Hello,
A(x)=x²-x-72 (m²)
L=(x+8) (cm)= (x+8)/100 (m)
We suppose here x≠-8
(in reality x²-x-72>0 ==>x<-8 or x>9
but x+8>0 ==> x>-8
then
only x>9 are solutions)
W=A(x)/ ((x+8)/100 )=100*(x²-x-72)/(x+8)= 100*(x-9)(x+8)/(x+8)=100*(x-9)

The answer is (3) -5 and 5.
Answer:
The cosine function to model the height of a water particle above and below the mean water line is h = 2·cos((π/30)·t)
Step-by-step explanation:
The cosine function equation is given as follows h = d + a·cos(b(x - c))
Where:
= Amplitude
2·π/b = The period
c = The phase shift
d = The vertical shift
h = Height of the function
x = The time duration of motion of the wave, t
The given data are;
The amplitude
= 2 feet
Time for the wave to pass the dock
The number of times the wave passes a point in each cycle = 2 times
Therefore;
The time for each complete cycle = 2 × 30 seconds = 60 seconds
The time for each complete cycle = Period = 2·π/b = 60
b = π/30 =
Taking the phase shift as zero, (moving wave) and the vertical shift as zero (movement about the mean water line), we have
h = 0 + 2·cos(π/30(t - 0)) = 2·cos((π/30)·t)
The cosine function is h = 2·cos((π/30)·t).
The pattern is that each number is decreasing by half