- $ D = \\\left( { - \\\infty ;\\\frac{4}{3}} \\\right)$.
- $ D = \\\left[ {\\\frac{3}{2};\\\frac{4}{3}} \\\right)$.
- $ D = \\\left[ {\\\frac{2}{3};\\\frac{3}{4}} \\\right)$.
- $ D = \\\left[ {\\\frac{4}{3}; + \\\infty } \\\right)$.