Question

Daca 2^a+2^-a=3 atunvi cat ii 4^a+4^-a ??

Answer 1

[tex]2^a+2^{-a}=3\\ \text{Prin ridicare la patrat se obtine:}\\ (2^a+2^{-a})^2=3^2\\ 4^a+2\cdot \underbrace{2^a\cdot 2^{-a}} + 4^{-a}=9\\ ~~~~~~~~~~~~~=1\\ 4^a+4^{-a}+2=9\\ \boxed{4^a+4^{-a}=7}[/tex]