1)

(x-2)/36=5/12

12*(x-2)=180

12x-24=180

12x=204

x=17

Проверка:

(17-2)/36=15/36=5/12

2)

(x-5)/23=36/92

92(x-5)=828

92x-460=828

92x=1288

x=14

(14-5)/23=9/23

36/92=9/23

3)

(3x-11)*36=252

108x-396=252

108x=648

x=6

4/(18-11)=4/7

36/63=4/7