Factoring an expression

Question

Factor he expression

 

-216x^3+1

 

A. (-6x+1)(36x^2+6x+1)

 

B. (-6x+1)^3

 

C. (-6x-1)(36x^2-6x+1)

 

D. prime polynomial

 

I know the problem is not a prime polynomial. I came up with -(6x-1)(36x^2+6x+1). This answer is not listed, What did I do wrong.

Answer 1

-216x^3+1

= 1 - (6x)^3

= (1-6x)(1+6x+36x^2)

= (-6x+1)(1+6x+36x^2)

 

So, the answer is A.

Answer 2

Right answer is

 

(-6x+1)(36x^2+6x+!)