a) \(-\left(\frac{3}{17}+\frac{2}{13}\right)-\left(-\frac{20}{17}+\frac{11}{13}\right)\)
\(=-\frac{3}{17}-\frac{2}{13}+\frac{20}{17}-\frac{11}{13}\)
\(=-\frac{3}{17}+\frac{20}{17}-\frac{2}{13}-\frac{11}{13}\)
\(=\frac{17}{17}-\frac{13}{13}\)
\(=1-1=0\)