Question

cum se rezolva: log3(5-√7) + log3 (5+√7) - log3 (2)? Unde 3 e baza.

Answer 1

$\displaystyle log_3(5- \sqrt{7} )+log_3(5+ \sqrt{7} )-log_32= \\ =log_3((5- \sqrt{7} )(5+ \sqrt{7} ))-log_32=log_3(25-7)-log_32= \\ =log_318-log_32=log_3 \frac{18}{2} =log_39=log_33^2=2log_33=2$