[tex]m + - \frac{2}{3} = - \frac{1}{3} \\ \\ m - \frac{2}{3} = - \frac{1}{3} \ / \ simplify \\ \\ m = - \frac{1}{3} + \frac{2}{3} \ / \ add \ \frac{2}{3} \ to \ each \ side \\ \\ m = \frac{1}{3} \ / \ simplify \\ \\ Answer: \fbox {m = 1/3} \ or \ \fbox {m = 0.3333} [/tex]