Answer:
D
Step-by-step explanation:
The equation of a parabola in vertex form is
y = a(x - h)² + k
where (h, k) are the coordinates of the vertex and a is a multiplier
Here (h, k) = (8, - 1), thus
y = a(x - 8)² - 1
To find a substitute (0, - 17), the coordinates of the y- intercept into the equation.
- 17 = a(0 - 8)² - 1
- 17 = 64a - 1 ( add 1 to both sides )
- 16 = 64a ( divide both sides by 64 )
a = = -
y = - (x - 8)² - 1 → D
Answer:
The sound intensity of a whisper is 333.3 times the reference intensity
Step-by-step explanation:
Given : The function gives the intensity of a sound in decibels, where x is the ratio of the intensity of the sound to a reference intensity.
A whisper has a sound intensity of 30 decibels.
To find : Use your graph to help you complete the following statement. The sound intensity of a whisper is times the reference intensity.
Solution :
Graph is attached which shows their intersection at (1000,30).
We can also verify by substituting value.
We have given that a whisper has a sound intensity of 30 decibels.
Therefore, y=30 , Let log base 10
Logarithmic property
The ratio of the intensity of the sound to a reference intensity is 1000 decibels
The sound intensity of a whisper is times the reference intensity is
The sound intensity of a whisper is 333.3 times the reference intensity.
