X-12=0
Х=12-0
Х=12
------------------------------------------
12-12=0
25+Х=25
Х=25-25
Х=0
--------------------------------
25+0=25
Х:108=1
Х=108:1
Х=108
-------------------------
108:108=1
Y:1=37
Y=37:1
Y=37
---------------------------------
37:1=37
X*15=0
Х=15*0
Х=0
-------------------------------
0*15=0
Х*18=18
Х=18:18
Х=1
1*18=18