Ответ:
\[\left(\frac{23}{30}-\frac{11}{28}\right)\cdot 42=\frac{23\cdot42}{30}-\frac{11\cdot42}{28}\]
\[=\frac{161}{5}-\frac{33}{2}=\frac{322}{10}-\frac{165}{10}=\frac{157}{10}\]
Ответ: \(\frac{157}{10}\)
\[\left(\frac{23}{30}-\frac{11}{28}\right)\cdot 42=\frac{23\cdot42}{30}-\frac{11\cdot42}{28}\]
\[=\frac{161}{5}-\frac{33}{2}=\frac{322}{10}-\frac{165}{10}=\frac{157}{10}\]
Ответ: \(\frac{157}{10}\)