(234 + х) - 456 = 178
234 + х - 456 = 178
х - 222 = 178
х = 178 + 222
х = 400
(х + 13,216) - 24,83 = 5,17
х + 13,216 - 24,83 = 5,17
х - 11,614 = 5,27
х = 5,27 + 11,614
х = 16,884
(8164 - х) - 2398 = 2557
8164 - х - 2398 = 2557
-х + 5766 = 2557
х = 5766 - 2557
х = 3209