Question

$frac{5^{n+1}-5^{n-1}}{2cdot 5^{n}}$

Answer 1

^ -степень
5^n+1 - 5^n-1 / 2*5^n =5^n (5 - 1/5) / 2*5^n = (24/5) / 2 =24/10 = 2,4

Answer 2

$frac{5^{n+1}-5^{n-1}}{2cdot 5^{n}}=frac{5^n(5^1-5^{-1})}{2cdot 5^{n}}=frac{5-frac{1}{5}}{2}=4frac{4}{5}:2=frac{24}{5}*frac{1}{2}=frac{12}{5}=2frac{2}{5}$