1)
(x - 7) + а = 23,
х = 9,
(9 - 7) + а = 23,
2 + а = 23,
а = 23 - 2,
а = 21,
2)
(11 + х) + 101 = а,
х = 5,
(11 + 5) + 101 = а,
а = 16 + 101,
а = 117