Answer:
C the 12th root of (8^x)
Step-by-step explanation:
This becomes 8 ^ x/4 ^ 1/3
We know that a^b^c = a^ (c*c)
8 ^(x/12)
The number of stamps with penny in terms of x is 
<em><u>Solution:</u></em>
Given that,
Ryan has x stamps in his collection
Number of stamps of Ryan = x stamps
Let the stamps with penny be "a"
Ryan has 6 times as many stamps as penny
Therefore,
Number of stamps in Ryan = 6 times as many stamps as penny

Thus number of stamps with penny in terms of x is 
Answer:
2x+3y+5
Step-by-step explanation:
Firstly, we remove the parenthesis since there is nothing in front of it.
There is a “+” sign in front of the parenthesis, it stays the same.
Secondly, we combine like terms. We combine the x’s, the y’s, and the normal numbers without a variable.
Finally, after combining the like terms. You end up with “2x+3y+5”.
The mean is calculated by adding up all of the given numbers and dividing by the number of numbers.
Lets, for ease of understanding, say that the first three number were 64...
Mean=(64+64+64)/3=192/3=64
Now, lets solve for the mean where 'x' is the unknown fourth number and 128 is the mean. (since, the answer said that when the fourth number was added the mean, 64, was doubled '64*2=128')
128=(64+64+64+x)/4
128=(192+x)/4
Multiply both sides by 4
512=192+x
subtract 192 from both sides
320=x
The missing number is 320..
Now lets double check our work.
Mean=(64+64+64+320)/4=512/4=128
Answer=320