А)
(х - 8) * 2/5 = 2
х - 8 = 2 : 2/5
х - 8 = 2 * 5 /2
х - 8 = 5
х = 5 + 8
х = 13
проверка:
(13 - 8) * 2/5 = 2
5 * 2/5 = 2
б)
2 1/3х - 2 1/3 = 2 1/3
2 1/3х = 2 1/3 + 2 1/3
2 1/3 х = 4 2/3
х = 4 2/3 : 2 1/3
х = 2
проверка:
2 1/3 * 2 - 2 1/3 = 2 1/3
4 2/3 - 2 1/3 = 2 1/3
2 1/3 = 2 1/3