Step-by-step explanation:
[tex] - 2 \times \frac{1}{2} \div 3 \times \frac{1}{2 } \\ - \frac{5}{2} \div \frac{7}{2} \\ - \frac{5}{2} \times \frac{2}{7} \\ = - \frac{5}{7} [/tex]