a)3725-1968-(437-x)=x+1320
3725-1968-437+x=x+1320
1320+x=x+1320
x cu x se simplifica.. deci ecuatia nu are solutii
b)12375-10371-(4375-x)=x-2371
12375-10371-4375+x=x-2371
x-2371=x-2371
ecuatie nu are solutii
c)7470-(x-375)-6845=1000
7470-x+375-6845=1000
-x=1000+6845-375-7470
-x=0
x=0