explain how you would factor completely x9 –27. PLEASE

Question

anonymous · Answer

do you know the formula for a Difference of two cubes? or does that sound familiar to you?

anonymous · Answer

it sounds familiar

anonymous · Answer

hmmmm. sounds familiar

anonymous · Answer

Thats what we are going to use to solve this problem, the formula you need to know is:
$$x^3-y^3 = (x-y)(x^2+xy+y^2)$$
@satellite lol

anonymous · Answer

so the cube root of 27 is 3 but what is the cube root of x^9??

anonymous · Answer

First, we need to get our problem in the right form.  So lets rewrite it with some cubes in it:
$$x^9-27 \Rightarrow (x^3)^3 - 3^3$$

anonymous · Answer

for the x^9, we change it to:
$$(x^3)^3$$

anonymous · Answer

good thinking joe

anonymous · Answer

oh now i understand it so after that do i just put it in the formula???

anonymous · Answer

@irvine yep, the formula will take care of it now.
@jimmy thank you :)

anonymous · Answer

oh heck no!

anonymous · Answer

o.O

anonymous · Answer

@elizated the answer is not 
$$(x^3+3)^3$$

anonymous · Answer

you need to use what joemath wrote above 
$$a^3-b^3=(a-b)(a^2+ab+b^2)$$ making the replacement 
$$a=x^2,b=3$$

anonymous · Answer

@joe thanks that help
@satellite thanks too because i got a lil confused at the end

anonymous · Answer

yes i see that.  joemath did all the work, but you still have to make the substitutions

anonymous · Answer

yes i know how to do that. but a=x^3 or x^2??