Решить уравнения

1) 21/31 - (х + 7/31) = 8/31

2) (х - 20/47) - 11/47 = 1/47

3) (31/59 - х) + 2/59=18/59

4) 40/71 - (12/71 + х) = 20/71

1) 21/31 - (х + 7/31) = 8/31

х + 7/31 = 21/31 - 8/31

х + 7/31 = 13/31

х = 13/31 - 7/31

х = 6/31

2) (х - 20/47) - 11/47 = 1/47

х - 20/47 = 11/47 + 1/47

х - 20/47 = 12/47

х = 12/47 + 20/47

х = 32/47

3) (31/59 - х) + 2/59 = 18/59

31/59 - х = 18/59 - 2/59

31/59 - х = 16/59

х = 31/59 - 16/59

х = 15/59

4) 40/71 - (12/71 + х) = 20/71

12/71 + х = 40/71 - 20/71

12/71 + х = 20/71

х = 20/71 - 12/71

х = 8/71