Breuken haakjesregel (reeks 1)

Bereken

\(-\left(\frac{-3}{10}\right)+\left(\frac{-9}{-13}\right)\)

\(-\left(\frac{-3}{10}\right)+\left(\frac{-9}{-13}\right)\\= \frac{3}{10}+\frac{9}{13}\\=\frac{39}{130}+\frac{90}{130}\\=\frac{39+90}{130}\\=\frac{129}{130}\)