a, $\dfrac{5}{2}-\dfrac{1}{2}x=\dfrac{2}{3}$
$\dfrac{1}{2}x=\dfrac{11}{6}$
$x=\dfrac{11}{3}$
Vậy $x=\dfrac{11}{3}$
b, $x:\dfrac{3}{4}+\dfrac{1}{4}=\dfrac{-2}{3}$
$x:\dfrac{3}{4}=\dfrac{-11}{12}$
$x=\dfrac{-11}{16}$
Vậy $x=\dfrac{-11}{16}$
c, $\dfrac{2}{3}+\dfrac{5}{12}:x=4$
$\dfrac{5}{12}:x=\dfrac{10}{3}$
$x=\dfrac{1}{8}$
Vậy $x=\dfrac{1}{8}$
d, $|x-\dfrac{2}{3}|:\dfrac{3}{2}=0,25$
$|x-\dfrac{2}{3}|=\dfrac{3}{8}$
$⇒x-\dfrac{2}{3}=\dfrac{3}{8}$ hoặc $x-\dfrac{2}{2}=\dfrac{-3}{8}$
$+,x-\dfrac{2}{3}=\dfrac{3}{8}$
$x=\dfrac{25}{24}$
$+,x-\dfrac{2}{3}=\dfrac{-3}{8}$
$x=\dfrac{7}{24}$
Vậy `x∈{\frac{25}{24},\frac{7}{24}}`
