1/2 = 18/18 * 1/2 = 18/36,
2/6 = 6/6 * 2/6 = 12/36,
5/9 = 4/4 * 5/9 = 20/36,
1/12 = 3/3 * 1/12 = 3/36,
7/18 = 2/2 * 7/18 = 14/36
3/5x=15
15*5x=3*1 - по пропорции
75x=3
x=75/3
x=25
Ответ:25
(х+2)-(х+1)=38
х+2-х-1=38
х-х=38-2+1
Ответ: 37