can someone tell me if this is prime, I can't figure it out x^3-729 for some reason I am stuck!!

Question

amistre64 · Answer

if 729  can be cube rooted, then this demonstrates a difference of cubes

amistre64 · Answer

9*81 = 729

9*9*9 = 729;  9^3 = 729.

this can be factored as a difference of cubes

anonymous · Answer

ok I get that part so now what do I need to do or how to I write it an answer form.

amistre64 · Answer

i think the general set up is:

x^3 - y^3 = (x-y) (x^2 +xy +y^2)

amistre64 · Answer

but if the question is asking for prime or not; then its not prime since both terms are ... real cubics for lack of a better term

anonymous · Answer

well it says factor but if not then it is prime
 x^3-729=??

amistre64 · Answer

then it factors into the general form; and keep an eye in the quadratic factor to see if its still factorable

amistre64 · Answer

if  y^2-4y^2  is negative then its prime across the reals