( 26 + 37 + x ) + ( 44 - 13 - 18 ) - 16 - 18 - 26 =51
( 63 + х ) + ( 44 - 13 - 18 ) - 16 - 18 - 26 =51
( 63 + х ) + 13 - 16 - 18 - 26 = 51
63 + х = 51 - 13 + 16 + 18 + 26
63 + х = 98
х = 98 - 63
х = 35
проверка:
( 26 + 37 + 35 ) + ( 44 - 13 - 18 ) - 16 - 18 - 26 = 98 + 13 - 16 - 18 - 26 =
= 111 - 16 - 18 - 26 = 51
