Question

Which is a sum of cubes? a3 + 18 a6 + 9 a9 + 16 a12 + 8
a3 + 18
a6 + 9
a9 + 16
a12 + 8

Answer 1

Answer: $a^{12}+8$

Step-by-step explanation:

let's check all the expressions

1. $a^3+18$

here 18 is not a perfect cube.

2. $a^6+9$

here 9 is not a perfect cube.

3.$a^9+16$

here 16 is not a perfect cube.

4.$a^{12}+8$

here 8 is a perfect cube, thus we can write above expression by using laws of exponents as

$(a^4)^3+2^3$

Thus, $a^{12}+8$ is a sum of cubes.

Answer 2

Answer:

D. a12 + 8

Step-by-step explanation:

I took the test and got it correct! :3