Without actually calculating the value of cubes find the value of $(1)^3+(2)^3+2(4)^3+(-5)^3+(-6)^3$. Also write the identity used Without actually calculating the value of cubes find the value of $(1)^3+(2)^3+2(4)^3+(-5)^3+(-6)^3$. 
Also write the identity used 

You can use the identity that if $a + b + c=0$, then $a^3 + b^3  + c^3 = 3abc$. So we can say that:


*

*$2^3 + 4^3 + (-6)^3  = 3\cdot 2\cdot 4\cdot -6 = -144$.

*$1^3 + 4^3 + (-5)^3 = 3\cdot 1\cdot 4 \cdot -5 = -60$.
Adding both, we get:
$1^3 + 2^3 + 2 (4)^3 + (-5)^3 + (-6)^3 = -204$
