$(2,4x-36):1\dfrac{5}{7}=-1$
$\to(2,4x-36):\dfrac{12}{7}=-1$
$\to 2,4x-36=-1.\dfrac{12}{7}$
$\to 2,4x-36=\dfrac{-12}{7}$
$\to 2,4x=\dfrac{-12}{7}+36$
$\to 2,4x=\dfrac{240}{7}$
$\to x=\dfrac{240}{7}:2,4$
$\to x=\dfrac{240}{7}:\dfrac{12}{5}$
$\to x=\dfrac{100}{7}$
Vậy $x=\dfrac{100}{7}$
$\dfrac{1}{3}x-0,5x=0,75$
$\to (\dfrac{1}{3}-0,5)x=0,75$
$\to \dfrac{-1}{6}x=\dfrac{3}{4}$
$\to x=\dfrac{3}{4}:\dfrac{-1}{6}$
$\to x=\dfrac{-9}{2}$
Vậy $x=\dfrac{-9}{2}$
$\dfrac{1}{2}x+\dfrac{3}{5}(x-2)=3$
$\to \dfrac{1}{2}x+\dfrac{3}{5}.x-\dfrac{3}{5}.2=3$
$\to \dfrac{1}{2}x+\dfrac{3}{5}.x-\dfrac{6}{5}=3$
$\to (\dfrac{1}{2}+\dfrac{3}{5})x=\dfrac{6}{5}+3$
$\to \dfrac{11}{10}x=\dfrac{21}{5}$
$\to x=\dfrac{21}{5}:\dfrac{11}{10}$
$\to x=\dfrac{42}{11}$
Vậy $x=\dfrac{42}{11}$
