Which expression is a sum of cubes?

-27a³b⁶+ 8a⁹b¹²

Step-by-step explanation:

In the expression above -27 is a perfect cube of -3, 8 is a perfect cube of 2.

The exponents of a and b in both terms in the expression are divisible by 3.

The cube root of x, that is ∛xⁿ=x∧(n/3) where n is an integer.

ANSWER

EXPLANATION

When we can write an expression in the form

then it is a sum of cubes.

To write a given sum as sum of cubes, then the coefficients of the terms should cube be numbers and the exponents of any power should be a multiple of 3.

This tells us that the first option will be the best choice.

We can rewrite this as:

We apply this property of exponents:

This gives us

Therefore the correct option is A