Answer:
a)59.125, b)67.5, c)None
Step-by-step explanation:
Mean = All values added up and divided by the number of values

Median = Put all numbers in order from least to most and use the middle one, if there are two, use the mean of those two
. The middle ones are 60 & 75 so 
Mode = The number that repeats more times. In this case none of them repeat.
Answer:
(y-5)(y-5) or (y-5)^2
Step-by-step explanation:
You can use a tangent:

We have opposite = 17 and adjacent = x.

substitute:
cross multiply
multiply both sides by √3

divide both sides by 3

Use the Pythagorean theorem:

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Other method.
triangle.
The sides are in the ratio 
Therefore

But what is the expression, you have to tell me so I can do it.