Question

Resolva as equações
A) log (x + 2 + log (x - 1 ) = 2
3 3

Answer 1

$log(x+2)+log(x-1)=2\\log((x+2).(x-1))=2\\log(x^2-x+2x-2)=2\\log(x^2+x-2)=2\\\\10^2=x^2+x-2\\100=x^2+x-2\\x^2+x-102=0\\\\\delta=1^2-4.1.-102\\\delta=1+408\\\delta=409\\\\x=\frac{-1(+/-)\sqrt{409}}{2.1}\\\\x=\frac{-1+\sqrt{409}}{2}\\\\x'=\frac{-1-\sqrt{409}}{2}$

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