How would the expression be rewritten using sum of cubes?
x cubed plus 64

X∧3+64. First you have to get the cubed root of both of the factors which they are
x and 4. 
You then have that as your first set of parentheses.
(x+4).
Now you have to really know how to set up the second/last parentheses. First you square your first factor, which is x. You then will use the opposite sign from the first parentheses which will be subtracting in this case. After you get that you have to multiply the two factors in the first parentheses which will give you 4x. You then will use the same sign from the first parentheses, which will give you plus. Finally, you will square the second factor from the first parentheses, which will give you 16. 
Your final answer should be 
(x + 4) (x∧2 - 4x + 16)