ta có : \(\dfrac{a}{b}=120\%\Leftrightarrow\dfrac{a}{b}=\dfrac{6}{5}\)
\(\Leftrightarrow\dfrac{a}{6}=\dfrac{b}{5}=\dfrac{a-b}{6-5}=\dfrac{-64}{1}=-64\)
\(\dfrac{a}{6}=-64\Leftrightarrow a=-384\)
\(\dfrac{b}{5}=-64\Leftrightarrow b=-320\)
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