tìm x a) (2/5-x)^3=-8/27 b)4/3:x=3/4:2/5 c) 1/2x:8/7=0,03:4/11

Bạn tham khảo!
$a)$ $($ $\dfrac{2}{5}$ $-$ $x$ $)$³ $=$ $\dfrac{-8}{27}$
$→$ $($ $\dfrac{2}{5}$ $-$ $x$ $)$³ $=$ $($ $\dfrac{2}{3}$ $)$³ và $($ $\dfrac{2}{5}$ $-$ $x$ $)$³ $=$ $($ $\dfrac{-2}{3}$ $)$³
$→$ $\dfrac{2}{5}$ $-$ $x$ $=$ $\dfrac{2}{3}$ và $\dfrac{2}{5}$ $-$ $x$ $=$ $\dfrac{-2}{3}$
$→$ $x$ $=$ $\dfrac{2}{5}$ $-$ $\dfrac{2}{3}$ và $x$ $=$ $\dfrac{2}{5}$ $-$ $\dfrac{-2}{3}$
$→$ $x$ $=$ $\dfrac{-4}{15}$ và $x$ $=$ $\dfrac{16}{15}$
$b)$ $\dfrac{4}{3}$ $:$ $x$ $=$ $\dfrac{3}{4}$ $:$ $\dfrac{2}{5}$
$→$ $\dfrac{4}{3}$ $:$ $x$ $=$ $\dfrac{15}{8}$
$→$ $x$ $=$ $\dfrac{4}{3}$ $:$ $\dfrac{15}{8}$
$→$ $x$ $=$ $\dfrac{32}{45}$
$c)$ $\dfrac{1}{2}$ $.$ $x$ $:$ $\dfrac{8}{7}$ $=$ $0.03$ $:$ $\dfrac{4}{11}$
$→$ $\dfrac{1}{2}$ $.$ $x$ $:$ $\dfrac{8}{7}$ $=$ $\dfrac{3}{275}$
$→$ $\dfrac{1}{2}$ $.$ $x$ $=$ $\dfrac{3}{275}$ $.$ $\dfrac{8}{7}$
$→$ $\dfrac{1}{2}$ $.$ $x$ $=$ $\dfrac{24}{1925}$
$→$ $x$ $=$ $\dfrac{24}{1925}$ $:$ $\dfrac{1}{2}$
$→$ $x$ $=$ $\dfrac{12}{1925}$
$FbBinhne2k88$