Question

Resolva a equação logarítmica   log 3 (x² + 3x -1) =2 

 

Answer 1

$log\ _3\ (x^2+3x-1) = 2\\\\\ 3^2 = x^2+3x-1\\\\ 9 = x^2+3x-1\\\\ x^2+3x-10=0\\\\\ \Delta = 9+40\\\\ \Delta = 49$

$x^1 = \frac{-3+7}{2} = \frac{4}{2} = 2\\\\ x^2 = \frac{-3-7}{2} = \frac{-10}{2} = -5$

Solução {-5,2}