a) \(\dfrac{-12}{16}=\dfrac{-15}{20}=\dfrac{-18}{24}=\dfrac{-21}{28}=\dfrac{-24}{32}=\dfrac{-27}{36}=\dfrac{-30}{40}=\dfrac{-33}{44}=\dfrac{-36}{48}=\dfrac{-39}{52}\)
\(=\dfrac{-42}{56}=\dfrac{-45}{60}=\dfrac{-48}{64}=\dfrac{-51}{68}=\dfrac{-54}{72}=\dfrac{-57}{76}=\dfrac{-60}{80}=\dfrac{-63}{84}=\dfrac{-66}{88}=\dfrac{-69}{92}\)
\(=\dfrac{-72}{96}=\dfrac{-75}{100}\)