For a popular broadway musical, the theater box office sold 356 tickets at $80 apiece, 275 tickets at $60 apiece, and 369 tickets at $45 apiece. how much money did the box office take in?

For 356 ticket, each ticket is $80, so all of those tickets cost 356 × 80 = $28,480.
For 275 ticket, each ticket is $60, so all of those tickets cost 275 × 60 = $16,500.
For 369 ticket, each ticket is $45, so all of those tickets cost 369 × 45 = $16,605.

For all of the tickets the box office took in you have to do:
28,480 + 16,500 + 16,605 = 61,585

The answer is $61,585.

What’s the equation you are trying to solve to get x?