2000:(2х+50)=2
(2х+50)=2000:2
2х+50=1000
2х=1000-50
х=475
---------------------
61-(3х+51)=1
3х+51=61-1
3х+51=60
3х=9
х=3
-----------------------
(8х-12)*15-200:4=10
(8х-12)*15=10+50
(8х-12)*15=60
8х-12=60:15
8х-12=4
8х=4+12
8х=16
х=2
--------------------
(49х+11)*5-293=7
(49х+11)*5=7+293
49х+11=300:5
49х+11=60
49х=60-11
49х=49
х=1
---------------------------------------
(5х+70):120+2=3
(5х+70):120=1
5х+70=1*120
5х+70=120
5х=120-70
5х=50
х=10