Помогите срочно .Номер 1090 1,2,3

1) [latex]( \frac{3}{4} + \frac{1}{20} )* \frac{1}{2}= ( \frac{15}{20} + \frac{1}{20} )* \frac{1}{2}= \frac{16}{20}* \frac{1}{2}= \frac{8}{20} = \frac{2}{5} [/latex] 2)[latex]( \frac{7}{12} - \frac{1}{3} )* \frac{16}{19} =( \frac{7}{12} - \frac{4}{12} )* \frac{16}{19} = \frac{3}{12}* \frac{16}{19} = \frac{1}{4}* \frac{16}{19} = \frac{4}{19} [/latex] 3) [latex](7 \frac{3}{5} - 2\frac{4}{15} )* \frac{9}{32} =( \frac{38}{5} - \frac{34}{15} )* \frac{9}{32} =( \frac{114}{15} - \frac{34}{15} )* \frac{9}{32} =\frac{80}{15} * \frac{9}{32} =[/latex] [latex]= \frac{16}{3} * \frac{9}{32} = \frac{3}{2} [/latex]