Breuken haakjesregel (reeks 2)

Bereken

\(+\left(\frac{-9}{-8}\right) +\left(\frac{-9}{-5}\right) -\left(\frac{2}{-7}\right)\)

\(+\left(\frac{-9}{-8}\right) +\left(\frac{-9}{-5}\right) -\left(\frac{2}{-7}\right)\\= \frac{9}{8}+ \frac{9}{5}+\frac{2}{7}\\=\frac{315}{280}+\frac{504}{280}+\frac{80}{280}\\=\frac{315+504+80}{280}\\=\frac{899}{280}\)