b: x/15=-2/3
nên x=-10
c: \(\Leftrightarrow\left(\dfrac{2}{3}x+\dfrac{3}{7}\right):\dfrac{11}{5}+\dfrac{2}{7}=1\)
\(\Leftrightarrow\left(\dfrac{2}{3}x+\dfrac{3}{7}\right):\dfrac{11}{5}=\dfrac{5}{7}\)
\(\Leftrightarrow x\cdot\dfrac{2}{3}+\dfrac{3}{7}=\dfrac{11}{7}\)
\(\Leftrightarrow x\cdot\dfrac{2}{3}=\dfrac{8}{7}\)
hay x=12/7
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