Without actually computing the cubes, find the value of : \( 48^3 – 30^3 – 18^3 \)
\[
48^3 – 30^3 – 18^3
\]
\[
= 48^3 + (-30)^3 + (-18)^3
\]
\[
\text{Since } 48 + (-30) + (-18) = 0
\]
\[
\therefore a^3 + b^3 + c^3 = 3abc
\quad \text{when } a+b+c=0
\]
\[
= 3(48)(-30)(-18)
\]
\[
= 77760
\]