\(\begin{array}{l}\frac{4}{{11}} = \frac{{28}}{{77}} < 1\\\,\frac{3}{7} = \frac{{33}}{{77}} < 1\\\frac{9}{8} > 1\\ \Rightarrow \frac{4}{{11}} < \frac{3}{7} < \frac{9}{8}\end{array}\)
\(\begin{array}{l}b)\,\\ + )\,\left\{ \begin{array}{l}\frac{5}{8} = \frac{{15}}{{24}}\\\frac{{19}}{{24}}\end{array} \right.\\ + )\,\left\{ \begin{array}{l}\frac{{13}}{{11}} = \frac{{26}}{{22}}\\\frac{{17}}{{22}}\end{array} \right. \Rightarrow \,\frac{{17}}{{22}} < \frac{{13}}{{11}}\,\,\,\,\left( 1 \right)\\ \Rightarrow \frac{{15}}{{24}} < \frac{{19}}{{24}}\,\,\,hay\,\,\,\,\frac{5}{8} < \frac{{19}}{{24}}\,\,\,\left( 2 \right)\\so\,sanh\,\,\frac{{17}}{{22}}\,\,\,va\,\,\,\frac{5}{8}\\\frac{5}{8} = \frac{{110}}{{176}}\\\frac{{17}}{{22}} = \frac{{136}}{{176}}\\ \Rightarrow \frac{5}{8} < \frac{{17}}{{22}}\,\,\,\,\left( 3 \right)\\so\,\,sanh:\,\,\frac{{19}}{{24}}\,\,va\,\,\frac{{17}}{{22}}\\\left\{ \begin{array}{l}1 - \frac{{19}}{{24}} = \frac{5}{{24}}\\1 - \frac{{17}}{{22}} = \frac{5}{{22}}\end{array} \right. \Rightarrow \frac{5}{{24}} < \frac{5}{{22}}hay\,\,\frac{{19}}{{24}} > \frac{{17}}{{22}}\,\,\,\,\left( 4 \right)\\tu\,\,\left( 1 \right);\,\,\,\left( 2 \right);\,\left( 3 \right);\,\,\left( 4 \right)\\ \Rightarrow \frac{5}{8} < \frac{{17}}{{22}} < \frac{{19}}{{24}} < \frac{{13}}{{11}}\end{array}\)
