Which is a completely factored form of 27x^3+y^6
1. (3x+y^2)^3
2. (3x+y^2)(9x^2+y^4)
3. (3x-y^2)(9x^2+3xy^2+y^4)
4. (3x+y^2)(9x^2-3xy^2+y^4)

Question

Which is a completely factored form of 27x^3+y^6
1. (3x+y^2)^3
2. (3x+y^2)(9x^2+y^4)
3. (3x-y^2)(9x^2+3xy^2+y^4)
4. (3x+y^2)(9x^2-3xy^2+y^4)

anonymous · Answer

can u tell me what does $a^3 + b^3 $ equal to?
u know $27x^3 + y^6 = (3x)^3 + (y^2)^3 $

anonymous · Answer

I have no idea how to do this Im trying to learn

anonymous · Answer

well,$$x^3 + b^3 = (a+b)(a^2+b^2 - ab )$$

anonymous · Answer

now put $a=3x $ and $b=y^2 $ in that equation

anonymous · Answer

* sry $a^3$ i put $x^3$ by mistake

anonymous · Answer

ok but where does the y^2 come from

anonymous · Answer

$y^6 = (y^2)^3 $

anonymous · Answer

oh ok

nnesha · Answer

take cube root for fist  one  and then take cube of second

nnesha · Answer

wait 
|dw:1420301495688:dw|

just write here 
don't worry about the signs yet 
i will tell you that later