The volume of a cube is found by using the formula l^3, where l is the side length. if the side length is 4x^3, what is the volume of the cube?
a. 64x^6
b. 12x^9
c. 4x^6
d. 64x^9

D. 64x^9
This is because 4x^3 is the side length and you substitute it into l^3
and you get (4X^3)^3
 (4X^3)^3 is the same as (4X^3) x (4X^3) x (4X^3)
1. (4X^3)^3
2. (4X^3) x (4X^3) x (4X^3)
3. (16X^6) x (4X^3)  
(remember when multiplied, exponents get added to each other)
4. 64X^9        
After multiplying all three of those you get 64X^9 D.
Hope this helps

The answer is the third choice