C. is the correct answer because (x+3)^2 is x^2+6x+9
Answer:

Step-by-step explanation:

If you are asked to find the 85th percentile, you are being asked to find a data value associated with an area of 0.85 to its left.
Percentile is a measure used in statistics indicating the value below which a given percentage of observations in a group of observations fall. For example, the 30 th percentile is the value below which 20% of the observations may be found.
Let's assume the frequency of sound be f and wave length is w.
Given that, the frequency of sound varies inversely as the wavelength.
So, we can set up an equation as following:
f*w = k Where k= constant of variation.
Other information is, the frequency of a musical note is 276 cycles per second when the wavelength is 1.2m.
So, next step is to plug in f = 276 and w = 1.2 in the above equation to get the value of k.
276 * 1.2 = k
So, k = 331.2
Next step is to plug in k = 331.2 in the above equation. So,
f * w = 331.2
Now we need to find the wave length : w when frequency : f = 600.
Therefore,
600 * w = 331.2

So, w = 0.552
Hence, the wave length is 0.552 m.
Hope this helps you!.
225, the square root of 225 is 15