If the price of each computer is 9000 yuan, 20 computers will be sold. If the price of each computer is reduced by 300 yuan, one more computer will be sold every day, How many sets do you sell every day? How many yuan is the maximum sales

If the price of each computer is 9000 yuan, 20 computers will be sold. If the price of each computer is reduced by 300 yuan, one more computer will be sold every day, How many sets do you sell every day? How many yuan is the maximum sales

The relationship between the daily sales y and the number of additional units x is y = (9000-300x) (20 + x) to y = - 300X ^ 2 + 3000x + 180000 = - 300 (x ^ 2-10x-600) = - 300 [(X-5) ^ 2-625] because (X-5) ^ 2 ≥ 0, when x = 5, y has the maximum value y = (...)

According to statistics, 20 computers can be sold every day when the price of each computer is 9000 yuan. If the price of each computer is reduced by 300 yuan, one more computer can be sold every day
Let the number of price cuts be X. write the relationship between the daily sales volume y and X

Sell one more at a time
Reduce x times and sell more x sets
y=(9000-300x)(20+x)

The price of a computer is 15% lower than the original price, which is 750 yuan lower. How much is the original price?

750 / 15% = 5000 yuan

The original price of the computer is reduced by M yuan and 20%. The current price is n yuan. How much is the original price

Original price n / (1-20%) + M = 5 / 4 * n + m yuan