simplify (-3)^-1 + (-1)^-3
\((-3)^{-1} + (-1)^{-3} = \frac{1}{(-3)^{1}} + \frac{1}{(-1)^{3}} = -\frac{1}{3} + \frac{1}{1} = -\frac{1}{3} + (-1) = -\frac{1}{3} - 1 = -1\frac{1}{3}\)
