Breuken haakjesregel (reeks 1)

Bereken

\(+\left(\frac{-9}{-13}\right)-\left(\frac{13}{-9}\right)\)

\(+\left(\frac{-9}{-13}\right)-\left(\frac{13}{-9}\right)\\= \frac{9}{13}+\frac{13}{9}\\=\frac{81}{117}+\frac{169}{117}\\=\frac{81+169}{117}\\=\frac{250}{117}\)