Practicing Success
The set of real values of x for which $\log _{0.2} \frac{x+2}{x} \leq 1$ is: |
$\left(-\infty, \frac{-5}{2}\right] \cup(0,+\infty)$ $\left[\frac{5}{2},+\infty\right)$ $(-\infty,-2) \cup(0,+\infty)$ none of these |
$\left(-\infty, \frac{-5}{2}\right] \cup(0,+\infty)$ |
$\log _{0.2} \frac{x+2}{x} \leq 1⇒\frac{x+2}{x} \geq \frac{1}{5}$ as base = 0.2<1 so $ \frac{x+2}{x}-\frac{1}{5}≥0⇒\frac{5x+10-x}{5x}≥0$ $⇒\frac{4x+10}{5x}≥0⇒\left(-\infty, \frac{-5}{2}\right] \cup(0,\infty)$ by wave curve method |