(7200-a*200)+2000=3400

Question

(7200-a*200)+2000=3400

Answer 1

(7200 - 200а) = 3400 - 2000
7200 - 200а = 1400
200а = 7200 - 1400
200а = 5800
а = 5800 : 200
а = 29

Answer 2

(7200-200a)+2000=3400 |:100
(72-2a)+20=34
72-2a=34-20
-2a=14-72
-2a=-58
a=29