х = 4 2/21
Пошаговое объяснение:
3 2/5÷(5 5/7- х)=2 1/10
17/5 : (40/7 - х) = 21/10
-х = 17/5 : 21/10 - 40/7
-х = 17/5 * 10/21 - 40/7
-х = 34/21 - 40/7
-х = -86/21
х = 86/21 = 4 2/21
