Решить уравнение 5: 7: 3/8=y: 28/75

5:7:3/8=у:28/75
5/7•28/75=у•3/8
(5•28)/(7•75)=у•3/8
4/15=у•3/8
у=4/15:3/8
у=4/15•8/3=(4•8)/(15•3)=32/45
проверка
32/45:28/75=32/45•75/28=
(32•75)/(45•28)=(8•5)/(3•7)=40/21
5:7:3/8=5/7•8/3=40/21