Bonjour,
[tex]A= \frac{-2}{7}= \frac{9}{7} \\\\
A= \frac{-2-9}{7}\\\\
\boxed{A= \frac{-11}{7}} \\\\
B= \frac{1}{5}+ \frac{4}{15} \\\\
B= \frac{3}{15}+ \frac{4}{15} \\\\
B=\frac{3+4}{15} \\\\
\boxed{B= \frac{7}{15} }\\\\
C= \frac{2}{3}+(- \frac{5}{6}) \\\\
C= \frac{4}{6}- \frac{5}{6} \\\\
C= \frac{4-5}{6} \\\\
\boxed{C= \frac{-1}{6}}\\\\
D= \frac{3}{20}- \frac{1}{12}\\\\
D= \frac{9}{60}- \frac{5}{60}\\\\
D= \frac{4}{60}\\\\
\boxed{D= \frac{1}{15}} [/tex]
