3x+1/14=3/7 ; 98/x-9=7 ; x+3/8=10 ; 2x-1/10=3/5 .

1) 3х + 1/14 = 3/7 3х = 3/7 - 1/14 3х = 6/14 - 1/14 3х = 5/14 х = 5/14 : 3 х = 5/14 * 1/3 х = 5/42 проверка: 3 * 5/42 + 1/14 = 3/7 15/42 + 3/42 = 18/42 18/42 = 18/42 2) 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 3) х + 3/8 = 10 х = 10 - 3/8 х = 9 8/8 - 3/8 х = 9 5/8 проверка: 9 5/8 + 3/8 = 10 9 8/8 = 10 10 = 10 4) 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