What is 125x9+64y12 written as a sum of cubes?

1 Answer
Dec 19, 2017

(5x3 + 4y4)(25x6 - 20x3y4 + 16y8)

Explanation:

The skeletal equation for the sum of cubes:
a3 + b3 = (a + b)(a2 - ab + b2)

In the expression 125x9 + 64y12,
a = 3(125x9) = 5x3 and
b = 3(64y12) = 4y4

Now, plug in the a and b values into the skeletal equation:

125x9 + 64y12 = (5x3 + 4y4)(25x6 - 20x3y4 + 16y8)