решить уравнения 1) 21/31 - (х + 7/31)=8/312)(х - 20/47) -

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