Not quite sure on this problem???

Which of the following is a factor of 512x3 - 125?

Answer choices:

8x + 5

64x2 + 80x + 25

64x2 + 40x + 25

None of the above

Question

Not quite sure on this problem???


Which of the following is a factor of 512x3 - 125? 

Answer choices: 
		
8x + 5
		
64x2 + 80x + 25
		
64x2 + 40x + 25
		
None of the above

anonymous · Answer

I think it's D

anonymous · Answer

512x3 - 125 is the difference between 2 perfect cubes and can be rewritten as (8x)^3 - 5^3.  The difference between 2 perfect cubes can be factored as follows: a^3 - b^3 = (a - b)(a^2 + ab + b^2).  Your "a" is 8x and your "b" is 5.

anonymous · Answer

So, you do have a factor in one of the choices.  Hint: it has 3 terms in it, so it's one of either B or C.

anonymous · Answer

C

anonymous · Answer

It'd be +40x....right?

anonymous · Answer

"C" is correct!  You got it!  Good job!  The answer is indeed 64x2 + 40x + 25

anonymous · Answer

Thank you!!!!! You're such a help!!!!!!!!!!!!!!!!!!!!!!!!