Question

log x(x - 5) = log 36​

Answer 1

Resposta:

$\text{Leia abaixo}$

Explicação passo-a-passo:

$log\: x(x - 5) = log\: 36$

$x(x - 5) = 36$

$x^2 - 5x = 36$

$x^2 - 5x - 36 = 0$

$x = \dfrac{-b \pm \sqrt{\Delta}}{2a}$

$\Delta = b^2 - 4.a.c$

$\Delta = (-5)^2 - 4.1.(-36)$

$\Delta = 25 + 144$

$\Delta = 169$

$x' = \dfrac{5 + \sqrt{169}}{2.1} = \dfrac{5 + 13}{2} = \dfrac{18}{2} = 9$

$x'' = \dfrac{5 - \sqrt{169}}{2.1} = \dfrac{5 - 13}{2} = \dfrac{-8}{2} = -4$

$\boxed{\boxed{\text{S} = \left\{\:9, -4\:\right \}}}}$