bư
A,-3/7.2/5+2/5.-5/14-2/5.9/7 =2/5(-3/7-5/14-9/7) =2/5.(-6/14-5/14-18/14) =2/5.-29/14 =-29/35 b,-25,4.(18,5+43,6-16,8):12,7 =-25,4.45,3:12.7 =(-25,4:12,7).45,3 =-2.45,3 =-90,6 c,x=-3,5.9/7 x=-9/2