The fourth national sports conference was held in Hefei in May 2010. In order to welcome the arrival of the fourth national sports conference, Hefei Xiaoyaojin amusement park speculated 1500000 yuan to introduce a amusement facility. If the maintenance cost is not included, it is estimated that 330000 yuan will be generated after the opening. After the opening of the amusement facility, the accumulated maintenance cost from the first month to the x month is y 10000 yuan, and y = ax & sup2; + BX; If we call the income and maintenance expenses as the net income w ten thousand yuan (1) if the maintenance cost is 20000 yuan in the first month and 40000 yuan in the second month, the function expressions of Y and X and W about X are obtained respectively; (2) a few months after the opening of the amusement park, the net income of the amusement park is the largest? How many ten thousand yuan is the largest income? (3) can the amusement park recover its investment in a few months? The net income of 10000 yuan is the income generated by deducting the investment and maintenance expenses.

The fourth national sports conference was held in Hefei in May 2010. In order to welcome the arrival of the fourth national sports conference, Hefei Xiaoyaojin amusement park speculated 1500000 yuan to introduce a amusement facility. If the maintenance cost is not included, it is estimated that 330000 yuan will be generated after the opening. After the opening of the amusement facility, the accumulated maintenance cost from the first month to the x month is y 10000 yuan, and y = ax & sup2; + BX; If we call the income and maintenance expenses as the net income w ten thousand yuan (1) if the maintenance cost is 20000 yuan in the first month and 40000 yuan in the second month, the function expressions of Y and X and W about X are obtained respectively; (2) a few months after the opening of the amusement park, the net income of the amusement park is the largest? How many ten thousand yuan is the largest income? (3) can the amusement park recover its investment in a few months? The net income of 10000 yuan is the income generated by deducting the investment and maintenance expenses.

(1) Substituting (1,2) (2,6) into y = ax & sup2; + BX, the solution is obtained
If a = 1, B = 1, then y = x & sup2; + X
w=33x-y=-x²+32x (x≥1,x∈N)
(2) When x = - 32 / (- 2) = 16, W is the largest
Now w = 256
(3) When w ≥ 150
-x²+32x≥150
The solution is 106 ≤ x ≤ 16 + 106 under 16 radical
When x = 6, the investment can be recovered
The answer should be right

An average of 8 TV sets can be sold at 2400 yuan per day in a shopping mall. It is found that 4 more TV sets can be sold every day when the price of this kind of TV sets is reduced by 50 yuan. (1) if a shopping mall wants to make a profit of 4800 yuan per day in the sales of this kind of TV sets, and at the same time make the people benefit, how much should each TV set be reduced? (2) When the price of each TV set is reduced by how much yuan, the daily sales profit of the shopping mall is the highest? What is the maximum profit?

(1) If the price is reduced by X Yuan, the profit w = (2400-2000-x) × (8 + 4 × X50) = - 225x2 + 24x + 3200, let w = 4800, the solution is X1 = 100, X2 = 200, ∵ in order to benefit the people, the price of each TV set should be reduced by 200 yuan; (2) the profit w = (2400-2000-x) × (8 + 4 × X50) = - 225x

Use a wall (the length of the wall is not more than 45m) and a 80m long fence to surround a rectangular site. How to make the area of the rectangular site 750m2

Let the length ab of the enclosed rectangle ABCD be x m, then the width ad is 12 (80-x) M. according to the meaning of the title, we get x · 12 (80-x) = 750, that is, x2-80x + 1500 = 0. By solving this equation, we get X1 = 30, X2 = 50