Giải thích các bước giải:
a.Ta có:
$\dfrac52x+\dfrac{72}{5}=\dfrac6{34}$
$\to \dfrac{5}{2}x+\dfrac{72}{5}-\dfrac{72}{5}=\dfrac{3}{17}-\dfrac{72}{5}$
$\to \dfrac{5}{2}x=-\dfrac{1209}{85}$
$\to x=-\dfrac{2418}{425}$
b.Ta có:
$2.7:(\dfrac{-1}{2}-x)=1\dfrac35$
$\to 2.7:(\dfrac{-1}{2}-x)=\dfrac85$
$\to \dfrac{-1}{2}-x=2.7:\dfrac85$
$\to -\dfrac12-x=\dfrac{27}{16}$
$\to x=-\dfrac{35}{16}$