5 4/15 - 3 4/7 * x = 4 2/3

3 4/7 * x = 5 4/15 - 4 2/3

3 4/7 * x = 79/15 - 14/3

3 4/7 * x = 79/15 - 70/15

3 4/7 * x = 9/15

3 4/7 * x = 3/5

x = 3/5 : 3 4/7

x = 3/5 : 25/7

x = 3/5 * 7/25

x = 21/125

Ответ: 21/125