According to the meaning of the question, the equation is: x+4x-8=452
5x=460
x=92
The unit price of schoolbag is 92 yuan, and the unit price of racket is 360 yuan.
(2) In the supermarket A: 452*75%=339 yuan.
If you are in supermarket B, you must spend 360 yuan to buy a racket first, and then you get three shopping rolls, which are worth 90 yuan, so you only need to spend 2 yuan to buy a schoolbag with shopping rolls, which is 360+2=362 (yuan) in supermarket B.
It's more cost-effective to buy it at supermarket a.