Resposta:

[tex]j)\\ \\ (-\frac{4}{9})*\frac{1}{2} =-\frac{4*1}{9*2} =-\frac{4}{18} =-\frac{2}{9} \\ \\ k)\\ \\ (+\frac{5}{4} )*(-\frac{4}{11} )=-\frac{5*4}{4*11} =-\frac{20}{44} =-\frac{5}{11} \\ \\ l)\\ \\ (+\frac{6}{10} )*(-\frac{1}{3} )=-\frac{6*1}{10*3} =-\frac{6}{30} =-\frac{1}{5} \\ \\ m)\\ \\ (-\frac{7}{2} )*(+\frac{3}{14} )*(-\frac{2}{3} )=+\frac{7*3*2}{2*14*3} =+\frac{42}{84} =+\frac{1}{2}[/tex]