-2/7-3/4×(-28) как???
-2/7-3/4*(-28)= -2/7+ 3*28/4= -2/7+3*4= -2/7+ 84/7= 82/7= 11 5/7
-2/7-3/4×(-28)=-2/7+21=-2/7+20 7/7=20 5/7