Question

Solve :
$9x^7+x^7+x$ for $x=7$

Answer 1

$9x^7+x^7+x=?$

$x=7$

$x^7=7^7=(1+6{)}^7=$

$9x^7+x^7+x$ at $x=7$

$10x^7+x\Rightarrow x(10x^6+1)$

$\Rightarrow 7\left(10x\right(7{)}^6+1)$

$\Rightarrow 7(10\times (49{)}^2\times \left(49\right)+1)$

$\Rightarrow 7\left[\right(10\left)\right(2401\left)\right(49)+1]$

$\Rightarrow 7[1176490+1]$

$\Rightarrow 8235437$

$\therefore 9x^7+x^2+x$ at $x=7$ is $8,235,437$