2.5: одна целая три четветрых(4.2-3.5)*(4/7)в квадрате

2,5 : 1 3/4 * (4,2 - 3,5) * (4/7)^2 = 16/49

1) 4,2 - 3,5 = 0,7 = 7/10
2) 2,5 : 1 3/4 = 25/10 : 7/4 = 25/10 * 4/7 = (25*2)/(5*7) = 50/35 = 10/7
3) 10/7 * 7/10 = 1
4) (4/7)^2 = 4/7 * 4/7 = 16/49
5) 1 * 16/49 = 16/49