Breuken verm. (reeks 3)

Vermenigvuldig de breuken

\(\frac{9}{-13} . \left(\frac{7}{-11}\right).\frac{12}{12}\)

\(\frac{9}{-13} . \left(\frac{7}{-11}\right).\frac{12}{12}\\=+\frac{9}{13}.\frac{7}{11}.\frac{1}{1}\\=+\frac{9.7.1}{13.11.1}\\=\frac{63}{143}\)