Question

(31*550-X)*120=10200

Answer 1

( 31 *550 -х) *120 =10 200

31* 550-х =10 200 :120

17 050 - х=85

х =17 050 - 85 

х =16 965

проверка :

( 31 * 550 - 16 965 )* 120 =10 200

Answer 2

(31*550-X)*120=10200

17050-х=10200/120

17505-х=85

х=17050-85

х=16965