Câu 5. (1 ,0 điểm) a) Tính: (1)/(7)cdot ((4)/(3))^2-(1)/(7):(9)/(11) Tìm x, biết: 2x+(1)/(4)=(3)/(5)

<p>a/&nbsp;$\frac{1}{7} \cdot\left(\frac{4}{3}\right)^2-\frac{1}{7}: \frac{7}{11}$</p><p></p><p></p><p>$\begin{aligned} &amp; =\frac{1}{7} \cdot \frac{16}{9}-\frac{1}{7} \cdot \frac{7}{9} \\ &amp; =\frac{1}{7}\left(\frac{16}{9}-\frac{7}{9}\right)=\frac{1}{7} \cdot 1=\frac{1}{7} \\ &amp; \text { b/ } 2 x+\frac{1}{4}=\frac{3}{5} \\ &amp; 2 x=\frac{3}{5}-\frac{1}{4} \\ &amp; 2 x=\frac{7}{20} \Rightarrow x=\frac{7}{40} \end{aligned}$</p><p></p>