Question

Find factors of 27+y^3

Answer 1

$y^{3} + 27$
$= y^{3} + 3^{3}$
$= (y+3)( y^{2} -3y + 3^{2} )$
$= (y+3)( y^{2} -3y+9)$

I applied the sum of cubes rule: $a^{3} + b^{3} = (a+b)( a^{2} -ab+b^{2} )$. 

Hope this may help you.