Find the value

Question:

Find the value

$1029-3 x^{3}$

Solution:

$=3\left(343-x^{3}\right)$

$=3\left((7)^{3}-x^{3}\right)$

$=3(7-x)\left(72+7 x+x^{2}\right)$

$\left[\because a^{3}-b^{3}=(a-b)\left(a^{2}+a b+b^{2}\right)\right]$

$=3(7-x)\left(49+7 x+x^{2}\right)$

$\therefore 1029-3 x^{3}=3(7-x)\left(49+7 x+x^{2}\right)$

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