Solution: If the price of each piece is reduced by X yuan, then each piece will make a profit of (40-X) yuan, and (20+2x) pieces can be sold every day. According to the meaning of the question, the equation can be formulated.
(40-x)(20+2x)= 1200
The sorted x2-30x+200 = 0.
The result is x 1= 10, x2=20.
Because we need to reduce the inventory as much as possible, the more we reduce the price, the faster the sales will be, so we have to reduce the price of each piece by 20 yuan.
A: Every shirt will be reduced in price, 20 yuan.
Summary: Minimizing inventory is the essential meaning of this equation. It is not difficult to get one that meets the meaning of the question, but it is easy to miss the requirement of "reducing inventory as soon as possible" in the examination of the question, which leads to mistakes. Please note that in addition, the price of each shirt in this question is reduced by X yuan, that is, the profit of each shirt is reduced by X yuan. Therefore, it is the key to solve the application problems seriously.
I wonder if it will help you.