Each of Exercises 7–18 contains six similar expressions. For each exercise evaluate the six expressions and note their similarities and differences. See Example 1.
$$\left(\frac{1}{6}\right)^{1},\left(-\frac{1}{6}\right)^{1},-\left(\frac{1}{6}\right)^{1},\left(\frac{1}{6}\right)^{-1},\left(-\frac{1}{6}\right)^{-1},-\left(\frac{1}{6}\right)^{-1}$$