a: =>5/9:x=1/5-4/7=7/35-20/35=-13/35
=>x=-175/117
b: \(\Leftrightarrow\dfrac{3}{2}\left(x-\dfrac{7}{6}\right)=\dfrac{5}{6}+\dfrac{5}{4}=\dfrac{25}{12}\)
\(\Leftrightarrow x-\dfrac{7}{6}=\dfrac{25}{18}\)
hay x=25/18+21/18=46/18=23/9
c: \(\Leftrightarrow-2x+\dfrac{9}{2}=\dfrac{4}{3}\cdot\dfrac{3}{4}=1\)
=>-2x=-7/2
hay x=7/4