The combined total profit is (17x + 2502) dollars
Solution:
Profit for each Mp3 player = $ 35
Profit for each DVD player = $ 18
Let x be the number of MP3 players sold last week
Number of MP3 players = x
Last week, Techwiz sold a combined total of 139 MPS and DVD players
Total number of mp3 and dvd sold = 139
Number of DVD player = 139 - x
Write an expression for the combined total profit (in dollars) Techwiz made from MP3 and DVD players last week.
Combined total profit = Number of MP3 players x Profit for each Mp3 player + Number of DVD player x Profit for each DVD player

Thus the combined total profit is (17x + 2502) dollars