Question

Сократите дробь  

Answer 1

(5^(n-1)-5^(n+1))/(2*5^n)=-12/5

Answer 2

$frac{5^{n+1}- 5^{n-1} }{2* 5^{n} } = frac{5^n(5^{1}- 5^{-1}) }{2* 5^{n} } = frac{5^{1}- 5^{-1} }{2 }= frac{5- frac{1}{5} }{2} =5- frac{1}{5} * frac{1}{2} = frac{49}{10}$