Question

[Trần Thị Đào]

tìm số x biết

a) \(\frac{7}{9}:\left(2+\frac{3}{4}x\right)+\frac{5}{9}=\frac{23}{27}\) b) \(\frac{-2}{3}.x+\frac{1}{5}=\frac{3}{10}\) c) \(\left|x\right|-\frac{3}{4}=\frac{5}{3}\)

Answer 1

[Khôngg Tồnn Tạii]

a. \(\frac{7}{9}:\left(2+\frac{3}{4}x\right)+\frac{5}{9}=\frac{23}{27}\)

\(\Rightarrow\frac{7}{9}:\left(2+\frac{3}{4}x\right)=\frac{23}{27}-\frac{5}{9}\)

\(\Rightarrow\frac{7}{9}:\left(2+\frac{3}{4}x\right)=\frac{8}{27}\)

\(\Rightarrow2+\frac{3}{4}x=\frac{7}{9}:\frac{8}{27}\)

\(\Rightarrow2+\frac{3}{4}x=\frac{21}{8}\)

\(\Rightarrow\frac{3}{4}x=\frac{21}{8}-2\)

\(\Rightarrow\frac{3}{4}x=\frac{5}{8}\)

\(\Rightarrow x=\frac{5}{8}:\frac{3}{4}\)

\(\Rightarrow x=\frac{5}{6}\)

b. \(\frac{-2}{3}x+\frac{1}{5}=\frac{3}{10}\)

\(\Rightarrow\frac{-2}{3}x=\frac{3}{10}-\frac{1}{5}\)

\(\Rightarrow\frac{-2}{3}x=\frac{1}{10}\)

\(\Rightarrow x=\frac{1}{10}:\left(\frac{-2}{3}\right)\)

\(\Rightarrow x=\frac{-3}{20}\)

c. \(\left|x\right|-\frac{3}{4}=\frac{5}{3}\)

\(\Rightarrow\left|x\right|=\frac{5}{3}+\frac{3}{4}\)

\(\Rightarrow\left|x\right|=\frac{29}{12}\)

\(\Rightarrow x=\frac{29}{12}\) hoặc \(x=-\frac{29}{12}\)