Here were 36,000 people at a ballgame in los angeles. the day's receipts from $12 reserved seats and $6 general-admission seats were $258,000 how many of each type of seat were sold?

R + g = 36000 ... r = 36000 - g

12r + 6g = 258,000

12 (36000 - g) + 6g = 258000

432000 - 12g + 6g = 258000

-12g + 6g = 258000 - 432000

-6g = - 174000

g = 174000/6

g = 29,000 < = = = general admission seats sold

r = 36000 - g

r = 36000 - 29000

r = 7,000 < = = reserved seats sold