Question

log de (x + 3) na base 2 + log de (x-4) na base 2 = 3

Answer 1

$log_{2} (x+3)+log _{2}(x-4)=3=\ \textgreater \ log _{2}(x+3)(x-4)=3=\ \textgreater \ \\ (x+3)(x-4)=2^3=\ \textgreater \ x^2-x-12-8=0=\ \textgreater \ x^2 -x-20=0 \\ D=(-1)^2-4.1(-20)=\ \textgreater \ D=1+80=81 \\ x= \frac{1-9}{2} =\ \textgreater \ x=-4oux= \frac{1+9}{2} =\ \textgreater \ x=5$
-4 não  serve