Tìm x: a) 1 5/27 + (3x - 7/9)^3 = 24/27 b) 2 |x| - 1/2 = 3/4 c) |2x - 1/3| + 5/6 =1

* Hướng dẫn giải

a)

$\begin{array}{l}1\frac{5}{27}+{\left(3x-\frac{7}{9}\right)}^3=\frac{24}{27}\\ {\left(3x-\frac{7}{9}\right)}^3=\frac{24}{27}-1\frac{5}{27}\\ {\left(3x-\frac{7}{9}\right)}^3=\frac{-8}{27}\\ 3x-\frac{7}{9}=\frac{-2}{3}\\ 3x=\frac{1}{9}\\ x=\frac{1}{27}\end{array}$

b)

$\begin{array}{l}2\left|x\right|-\frac{1}{2}=\frac{3}{4}\\ 2\left|x\right|=\frac{5}{4}\\ \left|x\right|=\frac{5}{8}\\ x=\pm \frac{5}{8}\end{array}$

c) 

$\begin{array}{l}\left|2x-\frac{1}{3}\right|+\frac{5}{6}=1\\ \left|2x-\frac{1}{3}\right|=\frac{1}{6}\\ 2x-\frac{1}{3}=\pm \frac{1}{6}\end{array}$

TH1:

$\begin{array}{l}2x-\frac{1}{3}=\frac{1}{6}\\ 2x=\frac{1}{2}\\ x=\frac{1}{4}\end{array}$

TH2:

$\begin{array}{l}2x-\frac{1}{3}=-\frac{1}{6}\\ 2x=\frac{1}{6}\\ x=\frac{1}{12}\end{array}$

Vậy $x=\frac{1}{4}$ hoặc $x=\frac{1}{12}$