super facil, mira te lo explico detalladamente :D
1)Log₂ X=-½ quiere decir [tex]2^{-\frac{1}{2}}=X \\ 2^{-1\cdot \frac{1}{2}}\ =\frac{1}{2}^{\frac{1}{2}}\\ \sqrt{\frac{1}{2}}=X [/tex]
2)log de x en base 0.3 = -2 =[tex]log_{0.3} x = -2\\ (\frac{3}{10})^{-2}=x\\ (\frac{10}{3})^2=X\\ \frac{100}{9}=X\\ X=11,\=1[/tex]
3) [tex]log\ de\ x \ en\ base\ p = -3\\ log_p\ X=-3\\ p^{-3}=X\\ X=(\frac{1}{p})^3\\ X=\frac{1}{p^3}[/tex]
4) log de 1/81 en base 3 = x
[tex]log_3\ \frac{1}{81} = x\\ 3^x=\frac{1}{81}\\ (81=9^2=3^4)\\ 3^x=\frac{1}{3^4}\\ X=-4[/tex]
esop :D
