Bonjour,
N =
[tex]\frac{ - 8}{9} \div \frac{7}{4} \\ = - \frac {8}{9} \times \frac{4}{7} \\ = - \frac{8 \times 4}{9 \times 7} \\ = - \frac{32}{63}[/tex]
P =
[tex]\frac{11}{3} \div \frac{ - 5}{4} \\ = - \frac{11}{3} \times \frac{4}{5} \\ = - \frac{11 \times 4}{3 \times 5} \\ = - \frac{44}{15}[/tex]
R =
[tex] - \frac{3}{5} + \frac{ - 10}{7} \\ = \frac{ - 3 \times 7 + ( - 10) \times 5}{5 \times 7} \\ = \frac{ - 21 - 50}{35} \\ = \frac{ - 71}{35} \\ = - \frac{71}{35}[/tex]
