a)\(\frac{5}{3}+\left(\frac{-2}{7}\right)-\left(-1,2\right)=\frac{5}{3}+\frac{-2}{7}+\frac{6}{5}=\frac{175}{105}+\frac{-30}{105}+\frac{126}{105}=\frac{271}{105}\)
b)\(\frac{-4}{9}+\left(\frac{-5}{6}\right)-\frac{17}{4}=\frac{-16}{36}+\frac{-30}{36}+\frac{-153}{36}=\frac{-199}{36}\)