25620+(13200-z)=30000
(13200-z)=30000-25620
(13200-z)=4380
13200-z=4380
-z=4380-13200
-z= -8820
z= 8820
25620+(13200-z) =30000
25620+13200-z=30000
38820-z=30000
-z=30000-38820
-z=-8820
z=8820
25620+(13200-z)=30000
(13200-z)=30000-25620
(13200-z)=4380
13200-z=4380
-z=4380-13200
-z= -8820
z= 8820
25620+(13200-z) =30000
25620+13200-z=30000
38820-z=30000
-z=30000-38820
-z=-8820
z=8820