(2)① The area of rectangle is xy, the area of circle AB is π×, and the area of circle BC is π×.
So w = 428 xy+400×π×+400×π× = 428 xy+400×π×+400×π× = 428 × (200-x)+400× 3.14×+400× 3.6543.100010000006
That is, w = 200-40000x+12560000;
(2) Only the government investment of 65.438 billion yuan cannot complete the construction task of this project, for the following reasons:
From ① we know that W = 200+ 1.056× >, so we can't;
③ From the meaning of the question, x≤y, that is, x≤ (200-x), then the solution is: x≤80, so 0≤x≤80.
According to the meaning of the question: W=200+ 1.056×=+6.842×, ranking =44 1, solved (please write down the reason), so you can only take x=79, so y = 200-79 = 1268.