The answer would be B because the 100 stays in there and you are adding 8% per year. Hope this helps.
From your equation, you can see that you have a difference of two cubes (aka two cubes being subtracted): 64, which is

, and

.
There is rule for the difference of two cubes:
The difference of two cubes is equal to the difference of the cube roots times a binomial, which is the sum of the squares of the roots plus the product of the roots.
That sounds pretty confusing, but it's much easier to understand when put mathematically. Let's say our two cubes are

and

. The difference of those two cubes is:

In our problem, a = 4 (since

= 64) and b = y (since

. Plug these values into the rule to find the factor of

:

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Answer:
Put the values of the variables in place of the variables in the expression, then do the arithmetic.
