Question

Simplify the expression:
$\frac{7^{n+3}-9\times 7^{n+1}}{31\times 7^{n+1}-3\times 7^{n+2}}$

Answer 1

$\frac{7^{n+3}-9\times 7^{n+1}}{31\times 7^{n+1}-3\times 7^{n+2}}$

$\frac{7^{n+1}(7^2-9)}{7^{n+1}(31-3\times 7)}$

$=\frac{40}{10}$

$=4$