If you have a difficult math problem, please ask your master to teach you, and ask a master to solve

Solution: (1) When 100 x 200

y=-225x+28, y=20-x-1010 when 200 x 300

y=-110x+32；

2) When 100 x 200 W = (x-40) y - (1520 + 480) x - 40) (-225x+28) - 2000 = 225x2 + 1565x-3120

225(x-195)2-78

x = 195, w max = -78

200＜x≤300，w=（x-40）y-（1520+480）(x-40)(-110+32)-2000

110x2+36x-3280

110(x-180)2-40

x = 180 -225 0,200 x 300w -80 loss, the minimum loss is 780,000 yuan (7 points) 3) According to the title, when 100 x 200, the relationship between w and x in the second year is.

w=(x-40)(-225x+28)-78When the total profit is just 18.42 million yuan, (x-40)(-225x+28)-78=1842 (8 points) can be obtained according to the title

Finishing, get x2-390x+38000=0

solution, x1 = 190, x2 = 200

To make a total profit of 18.42 million yuan in two years, the unit price of sales can be set at 190 yuan or 200 yuan (9 cents).

For y=-225x+28, y decreases as x increases.

The minimum number of split edges is 56The detailed answer process is as follows:

Every 11 rows are painted with the same color, then there are at least 33+33=66 strips on the divider.

The cost of each toy puppy is $x.

Then, the total cost of selling on the first day is 98x yuan, and the total cost of selling on the second day is 130x yuan;

The profit of the second day is 40% * 130x yuan, the amount of money from selling toys per day minus the cost is the profit, it is known that the amount of money from selling toy puppies on the first day is as much as the amount of money earned on the second day, the equation:

98x+420 130x+40%*130xThe solution is x=5 (yuan).

(1) When I first read the first question, I was also dizzy, so we might as well set the corner AOC as X. x<90

So isn't EOC half of AOB + AOC? （90+x）/2

If EOD is required, just subtract DOC from EOC, and OD is the angular bisector of AOC, then DOC=X 2, EOD=EOC-DOC=(90+X) 2-X 2=45+X 2-X 2=45°

2) When the angle AOB = M°, how many degrees is the angle doe equal to? We have already solved the above, replace x with m, the result is not the same, the problem condition AOB is an acute angle, and DOE is always equal to 45°

2.The term that does not contain xy is (2x) 3-3[(x) 2]y+kxy-5x[(y) 2]+4xy-3 without k*x*y, we write the formula better, 2x 3-3x y+kxy-5xy +4xy-3, that is, we kxy+4xy=0, and the rest don't worry about it, so k=-4, how about it, it's simple

3.The expression of the title is a bit vague, but it should be like this, mx (2a+2)y +5 2xy (3b+4), if this is the case, then it is simple, look at it, m=-5 2

2a+2=1

3b+4=2, then put m=-5 2

a=-1/2

b=-2 3 generations will go in.

I'll write it carefully for you.

1.(as an auxiliary line OA with respect to the OE symmetry line).

Set the angle aoc=x

angular aoe=y

So the angle boc=90+x, the angle boe=90-y;

So 2(90-y)=90+x; (0 degrees, since the angle doe = x 2 + y, the angle doe = 45 degrees 2.)Same as question 1, the angle aoc=x, the angle aoe=y, so the angle doc=angle doa=x 2;

So the angle boc = x + m, so the angle eoc = angle boc 2 = x + y;

So we get (x+m) 2=x+y;

Simplified m=x+2y;

Since the angle doe=x2+y=m2;

Final Result. The degree of the angle doe is 45°, and when the angle aob=m°, the angle doe is equal to m 2 The answer on the first floor is wrong!! ～

There is also the first question and the second question, don't do this during the exam, you should write it.

When the angle AOB=M°, the angle DOE is equal to (90+M)2-M2=45

After A is done as AC BF to C, in RT ABC, ABC=90°-60°=30°, AC=1 2AB=160<200

City A will be affected by the typhoon.

With A as the center of the circle and 200 as the radius, draw the arc to cross BF at D and E, and in RT ACD, CD= (AD -AC)=120

de=2×120=240

240 60 = 4, A: The time affected by the typhoon is 4 hours.

Answer: (1) City A will be affected by the typhoon, and if it crosses the perpendicular line of A as BF and intersects with point O, then AO is the shortest distance between the center of the typhoon and City A. Because the angle ABO=30 degrees, AO=160, City A will be affected by the typhoon.

2) This question needs to pass a to make a circle with a radius of 200, and at bf intersect two points, you can set it to m,n, and then find the length of mn, according to the Pythagorean theorem, fm=120, and then multiply by 2, that is, you can calculate mn=240, Mn is the process of the typhoon affecting city A, so the required time is divided by 240 by 60 to get 4, so the typhoon will affect city A for 4 hours.

It will be 4 hours.

1) The perpendicular line of BF is 160 km <200 km) if the perpendicular point D is 160 km 2) the side of the right triangle with AD as the right angle, if it is not affected by the typhoon, the side corresponding to the right angle is at least 200 km.

According to the Pythagorean definition, the other side on the BF is at least 120 km, note that both sides of point C can be triangular shapes.

The landlord can make his own drawings to make it easier to understand.