Question:
Find the value
$1029-3 x^{3}$
Solution:
$=3\left(343-x^{3}\right)$
$=3\left((7)^{3}-x^{3}\right)$
$=3(7-x)\left(72+7 x+x^{2}\right)$
$\left[\because a^{3}-b^{3}=(a-b)\left(a^{2}+a b+b^{2}\right)\right]$
$=3(7-x)\left(49+7 x+x^{2}\right)$
$\therefore 1029-3 x^{3}=3(7-x)\left(49+7 x+x^{2}\right)$