X- 100 Find out how much the unit price will increase.
(x- 100)/ 10 Find out the reduced sales.
Originally it was 200,000 yuan 100, so y = 20-(x- 100)/ 10 is calculated as y =-x/ 10+30.
(2)
Annual sales x*y
Production cost x*40
Because (annual profit = annual sales-production cost-investment)
z=xy-40x-500
Generation y goes in (note: x n represents the n power of x)
z=-x^2/ 10+30x-40x-500
Calculated z =-x y/ 10- 10x-500.
(3)
160 generation into x to find z.
Then return to the Z generation and find z =-x 2/ 10+30x-40x-500.
Find x (quadratic equation x has two solutions, one is 160, and the other is what we want).