98/х - 9 = 7
98 : х = 7 + 9
98 : х = 16
х = 98 : 16
х = 98/16
х = 6 2/16
х = 6 1/8
проверка:
98 : 6 1/8 - 9 = 7
98 : 49/8 - 9 = 7
98 * 8/49 - 9 = 7
2 * 8 - 9 = 7
16 - 9 = 7
7 = 7
2х - 1/10 = 3/5
2х = 3/5 + 1/10
2х = 6/10 + 1/10
2х = 7/10
х = 7/10 : 2
х = 7/10 * 1/2
х = 7/20
проверка:
2 * 7/20 - 1/10 = 3/5
14/20 - 1/10 = 3/5
7/10 - 1/10 = 3/5
6/10 = 3/5
3/5 = 3/5