Question

Ajutati-ma va rog!
[tex] log_{7} (3- \sqrt{2} )+ log_{7} (3+ \sqrt{2} )
[/tex]

Answer 1

$log_{7} (3- \sqrt{2} )+ log_{7}(3+ \sqrt{2} ) =$

Folosim formula $log_{a}b+ log_{a} c= log_{a} (b*c)$

$log_{7} (3- \sqrt{2} )(3+ \sqrt{2} )=$
Folosim formula $(a-b)(a+b)= a^{2}- b^{2}$
$log_{7} ( 3^{2}- \sqrt{2} ^{2} } )$
$log_{7} (9-2)$
$log_{7} 7=1$