Ответ:\(1\frac{5}{19}\cdot\left(6-3\frac{5}{8}\right)=\frac{24}{19}\cdot\left(6-\frac{29}{8}\right)=\frac{24}{19}\cdot\frac{19}{8}=3\).\((6,3:1,4-2,05)\cdot1,8=(4,5-2,05)\cdot1,8=2,45\cdot1,8=4,41\).Ответ: а) 3; б) 4,41.