Techwiz electronics makes a profit of $35 for each mp3 player sold and $18 for each dvd player sold. last week, techwiz sold a combined total of 113 mp3 and dvd players.
let x be the number of mp3 players techwiz sold last week. write an expression for the combined total profit (in dollars) techwiz made from mp3 and dvd players last week.

Total number of MP3 and DVD players TechWiz sold last week 113
Number of MP3 players TechWiz sold last week = x
Then
Number of DVD players TechWiz sold last week = 113 - x
Amount of profit made by TechWiz on each MP3 player = $35
Amount of profit made by TechWiz on each DVD player = $18
Then
Total profit made by TechWiz
last week can be expressed as = 35x + 18(113 - x)
                                                  = 35x + 2034 - 18x
                                                  = 17x + 2034
I hope the answer and the process is clear to you.