a) \(\dfrac{-2}{7}\)+ \(\dfrac{2}{7}\): \(\dfrac{3}{5}\)

= \(\dfrac{-2}{7}\)+ \(\dfrac{2}{7}\) . \(\dfrac{5}{3}\)

= \(\dfrac{-2}{7}\)+ \(\dfrac{10}{21}\)

= \(\dfrac{-6}{21}\)+ \(\dfrac{10}{21}\)

=\(\dfrac{\left(-6\right)+10}{21}\)

=\(\dfrac{4}{21}\)

b) \(\dfrac{-8}{19}\)+ \(\dfrac{-4}{21}\)- \(\dfrac{17}{21}\)+ \(\dfrac{27}{19}\)

= \(\dfrac{-8}{19}\)+ \(\dfrac{-4}{21}\)+ \(\dfrac{17}{21}\)+ \(\dfrac{27}{19}\)

=(\(\dfrac{-8}{19}\)+ \(\dfrac{27}{19}\)) + ( \(\dfrac{-4}{21}\)+\(\dfrac{-17}{21}\))

=