Practicing Success
Solution set of the inequality $5^{x+2}>\left(\frac{1}{25}\right)^{\frac{1}{x}}$ is: |
$(-2,0)$ $(0, \infty)$ $(-5,5)$ $(-2,2)$ |
$(0, \infty)$ |
We have $5^{x+2}>\left(\frac{1}{25}\right)^{\frac{1}{x}}\left(\begin{array}{l}\text { If}~~a>1 \text {, than } \\ a^m>a^n \Rightarrow m>n\end{array}\right)$ $\Rightarrow 5^{x+2}>5^{-\frac{2}{x}}$ $\Rightarrow x+2>-\frac{2}{x}$ $\Rightarrow\left(\frac{x^2+2 x+2}{x}\right)>0$ as $(x^2+2x+2)=(x+1)^2+1>0$ always checking for $\frac{1}{x}$ only $\Rightarrow \frac{1}{x}>0 \Rightarrow x \in(0, \infty)$ Hence (2) is the correct answer. |