a: \(\dfrac{17}{320}=\dfrac{17\cdot1}{320\cdot1}=\dfrac{17}{320}\)
\(\dfrac{-9}{80}=\dfrac{-9\cdot4}{80\cdot4}=\dfrac{-36}{320}\)
b: \(\dfrac{-7}{10}=\dfrac{-7\cdot33}{10\cdot33}=\dfrac{-231}{330}\)
\(\dfrac{1}{33}=\dfrac{1\cdot10}{33\cdot10}=\dfrac{10}{330}\)
c: \(\dfrac{-5}{11}=\dfrac{-5\cdot140}{11\cdot140}=\dfrac{-700}{1540}\)
\(\dfrac{3}{20}=\dfrac{3\cdot77}{20\cdot77}=\dfrac{231}{1540}\)
\(\dfrac{9}{70}=\dfrac{9\cdot22}{70\cdot22}=\dfrac{198}{1540}\)
d: \(\dfrac{10}{42}=\dfrac{5}{21}=\dfrac{5\cdot44}{21\cdot44}=\dfrac{220}{924}\)
\(\dfrac{-3}{28}=\dfrac{-3\cdot33}{28\cdot33}=\dfrac{-99}{924}\)
\(\dfrac{-55}{132}=\dfrac{-55\cdot7}{132\cdot7}=\dfrac{-385}{924}\)
