The vol. of a cube of side length s is V=s^3.
So, if the side length is 5a+4b, then the volume of the cube is
V(a, b) = (5a+4b)^3. This could, of course, be expanded, using the binomial theorem, but there's no point in doing so.
By the binomial theorem,

where

Then the coefficients of the
terms in the expansion are, in order from
to
,





The Answer would be C, because if you divide 3/4 by 2/3 you have to switch numerators and denominator for 2/4, once you multiply that you get 9/8 you change that to a mixed number. Then you get C
Let’s take the number .666666 repeating
If we turn it into a fraction it’s 2/3.
It doesn’t matter how many numbers repeat to write a fraction.
Hope this helps.