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

1)3х + 1/14 = 3/73х = 3/7 - 1/143х = 6/14 - 1/143х = 5/14х = 5/14 : 3х = 5/14 * 1/3х = 5/42проверка:3 * 5/42 + 1/14 = 3/715/42 + 3/42 = 18/4218/42 = 18/422)98/х - 9 = 798 : х = 7 + 998 : х = 16х = 98 : 16х = 98/16х = 6 2/16х = 6 1/8проверка:98 : 6 1/8 - 9 = 798 : 49/8 - 9 = 798 * 8/49 - 9 = 72 * 8 - 9 = 716 - 9 = 77 = 73)х + 3/8 = 10х = 10 - 3/8х = 9 8/8 - 3/8х = 9 5/8проверка:9 5/8 + 3/8 = 109 8/8 = 1010 = 104)2х - 1/10 = 3/52х = 3/5 + 1/102х = 6/10 + 1/102х = 7/10х = 7/10 : 2х = 7/10 * 1/2х = 7/20проверка:2 * 7/20 - 1/10 = 3/514/20 - 1/10 = 3/57/10 - 1/10 = 3/56/10 = 3/53/5 = 3/5