الف) $\frac{4}{25} - (\frac{-6}{5}) \div \frac{10}{8} =$ ب) $\frac{1 - (\frac{1}{7} \times \frac{-5}{7})}{\frac{1}{3} \times \frac{2}{3} - (\frac{1}{2} + 1)} =$

الف) $\left. \begin{matrix} a \perp b \\ a \perp c \end{matrix} \right\} \Rightarrow b \dots c$ ب) $\left. \begin{matrix} d \parallel e \\ d \parallel f \end{matrix} \right\} \Rightarrow e \dots f$