Hello, well there are a few ways to write this. Here is one outlook.
Bruce bought three boxes of tiles with the same number of tiles in each.
x = number of tiles
3 = number of boxes
3x = total number of tiles.
Make note, the problem is asking for an expression for how many tiles he used and not the total number of tiles he has. Anyways, the problem then tells us he had to go get 3 more boxes but he used only 2 tiles out of the last box. So he used 2x + 2 tiles We put this together and we have
3x + 2x + 2
5x + 2
Number of tiles Bruce used = 5x + 2
We do the same for Felicia:
She gets 5 boxes, which = 5x. Then she had to go back and just get 5 tiles. So we have:
5x + 5
Number of tiles Felicia used = 5x + 5
