1)37/76 - (69/76 - х) = 15 /76  2) (х- 12/63)-

1)37/76 - (69/76 - х) = 15 /76
37/76 - 69/76 +х = 15 /76
-32/76+х = 15 /76
х = 15 /76 + 32/76
х =47 /76
2)(х- 12/63)- 38/63 = 4/63
х- 12/63- 38/63 = 4/63
х- 50/63 = 4/63
х =  4/63 + 50/63
х =  54/63=6*9/7*9
х =  6/7
3) 5/18 + (15/18 - (х-7/18)) = 11/18
5/18 + 15/18 - х + 7/18 = 11/18
27/18 - х = 11/18
27/18 - 11/18 = х
16/18 = х
х = 8/9
4)18/19 - ( 8/19 + ( 14/19 - х)) = 2/19
18/19 -  8/19 -( 14/19 - х)) = 2/19
18/19 -  8/19 - 14/19 + х = 2/19
10/19 - 14/19 + х = 2/19
х = 2/19 + 14/19 - 10/19
х = 6/19