Question

Which expression is a sum of cubes?

Answer 1

A cube is an integer that you can get by multiplying a number by itself 3 times.
e.g.: 1 * 1 * 1 = 1; therefore 1 is a cube.
e.g.: 3 * 3 * 3 = 27; therefore 27 is a cube.

Two cubes added together can be factorized into a simpler form.

i.e.:
$x {3} + y {3} = 0$
can be simplified into:
$(x + y)(x^{2} - xy + y^{2} )$