x3y3 + z3
5x3 + 40y6
8y3 - 27
We are suppose to do these but there don't explained how to do this
Hello,
Rewrite all this stuff :
$\displaystyle =(xy)^3+z^3$
$\displaystyle =5(x^3+8y^6)=5(x^3+(2y^2)^3)$, because $\displaystyle y^6=y^{2 \cdot 3}=(y^2)^3$5x3 + 40y6
$\displaystyle =(2y)^3+(-3)^3$8y3 - 27
Now, there is a formula that would help :
$\displaystyle a^3+b^3=(a+b)(a^2-ab+b^2)$