X-9=14
X=14+9
X=23
23-9=14
14=14
-------------------
5+х=52
Х=52-5
X=47
5+47=52
52=52
--------------------
x+25=40
X=40-25
X=15
15+25=40
40=40
--------------------
50-x=12
X=50-12
X=38
50-38=12
12=12
-------------------
63-x=27
x=63-27
x=36
63-36=27
27=27
--------------------
x-48=24
x=24+48
x=72
72-48=24
24=24