a. 2345-1254=x+675
1091=x+675
x+675=1091 => x=1091-675=416
b.x-1456=6453-2976
x-1456=3477 => x=3.477+1.456=4.933
c.4214-x=897+1430
4214-x=2.327 => x=4214-2327=1.887
