Question

Which polynomial represents a sum of cubes?

x^3 - 64

8x^3 + 125

16x^3 + 1

27x^3 + 4

Answer 1

8x³ + 125

Explanation:

Cubes: look for the exponent 3 and for perfect cubes such as 1, 8, 27, ...

8x^3 + 125 is a sum, and 8 is a perfect cube (the cube of 2), and x^3 is a cube, and 125 is a cube.

Thus, the correct answer is 8x^3 + 125 (which is equivalent to

(2x)³ + 5³).