5la puterea 2 + 5 la puterea -2=?

Răspuns :

5² + 5⁻² =

= 25 + 1/25

= (625  + 1)/25

= 626/25

[tex]S = 5^2+5^{-2}\Big|\cdot 5^2\\ \\ 5^2\cdot S = 5^4+5^0\\ \\ 25S = 625+1\\ \\ S = \dfrac{626}{25}[/tex]