a. The company produces 52 boxes per hour. Then, after 3 hours they produce 52*3 = 156 boxes. If they had 404 boxes after 3 hours, then they started with 404 - 156 = 248 boxes.
Given that they produce 52 boxes per hour, then after h hours, they produce 52h boxes. Therefore, the number of boxes, b, as a function of the number of hours, h, is:
b = 248 + 52h
b. Replacing with h = 8, we get:
b = 248 + 52(8)
b = 248 + 416
b = 664
There will be 664 boxes after an 8-hour shift