1. How many days does it take for the two teams to finish alone?
2. If the cooperation between Party A and Party B is completed after 6 days, it will cost 80,000 yuan, and the two teams will discuss the distribution of this money according to the completed workload. How much will each team pay? (2) m = x 2-8x+20, n = x 2+4x-3, and find the relationship between m and n.
Given x=√3- 1, find (x+ 1) 2-4 (x+ 1)+4 (3). As shown in the figure, in △AEC, angle AEC is an acute angle, point B is the midpoint of line segment AC, point D is the midpoint of line segment CE, and quadrilaterals BCEF and CDHN. It is proved that △FMH is an isosceles right triangle
(4) It is known that real numbers A, B and C satisfy a? +b？ = 1，b？ +c？ =2，c？ +b？ =2, so what is the maximum value of ab+bc+ca? (5) Southwest China suffered a once-in-a-century drought in 20 10, but this year, a city was less affected by the construction of a "forest city". According to statistics, in 2009, the city planted 500 million trees, saving 300 million cubic meters of water. If 500 million trees are planted every year in the future, the construction of "forest city" will be fully completed by 20 15. By then, trees can maintain water conservation for a long time 1 1 m3. Q: (1) During the seven years from 2009 to 20 15, how many billion trees were planted in this city? (2) If 2009 is taken as the first year, it is assumed that the water-holding capacity y (100 million cubic meters) of trees is a linear function with X years, and the analytical expression of this function is obtained, so as to find out how much water can be saved by the third year (i.e. 20 1 1 year). (6) The starting price of taxis in a city is 7 yuan (that is, all drivers within 3 kilometers must pay 7 yuan fare), which reaches or exceeds 3 kilometers. For every increase of 1 kilometer/6 yuan fare, Xiaoming pays 16 yuan from place A to place B (the payment follows the principle of "rounding off", and the part less than 0.5 yuan is ignored, and 0.5 yuan handles the answer as 65. Let the work efficiency of B be X and A be X+561/X+1(X+5)] =1. If you divide by the denominator, you will get 6(x+5)+6x=x2+5x.
The sorted x2-7x-30=0.
Decomposition is (x- 10)(x+3)=0.
So x= 10 or x=-3 (it doesn't conform to the meaning of the actual problem, so it is omitted).
Answer: Team A needs 65,438+05 days and Team B needs 65,438+00 days. The workload of team A in six days is 6/ 15, which is 2/5, and that of team B in six days is 3/5, so team A should get 80,000 * 2/5 = 32,000 yuan, and team B should get 80,000 yuan.
=x^2-8x+20-(x^2+4x-3)
=x^2-8x+20-x^2- 12x+23
=- 12x+23
(1) when x
(2) when x >; February 23rd, 2002
Solution: (x+ 1) 2-4 (x+ 1)+4.
=(x+ 1-2)^2
=(x- 1)^2
Use BM and DM to connect x=√3- 1 generation (X- 1) 2 = (√ 3-2) 2 = 7-4 √ 3 (III).
∫B is the midpoint of AC, and m is the midpoint of AE.
∴BM is the center line of the triangle trump card.
∴BM= 1/2CE
And d is the midpoint of CE.
∴CD= 1/2CE
∴BM=CD
Similarly, the quadrilateral CDHN is a square.
∴CD=DH
∴BM=DH
Similarly, it can be proved that DM=FB.
∫DM∨BC，BM∨CD
∴ quadrilateral BMDC is a parallelogram.
∴∠CBM=∠CDM
∠∠FBC =∠HDC = 90。
∴△FBM≌△MDH
∴FM=MH,∠MBF=∠HMD
∠∠CBM =∠CAM+∠BMA
∴∠CAM+∠BMA+∠HMD+∠FMB=90
∫AC∨MD
∴∠CAM=∠DME
∴∠DME+∠BMA+∠HMD+∠FMB=90
∴∠FMH=90
∴△FMH is an isosceles right triangle (4)∫a? +b？ = 1 ∴﹙a-b﹚？ = 1-2ab﹙ 1﹚
∵b？ +c？ =2 ∴﹙b-c﹚？ =2-2bc﹙2﹚
∵c？ +a？ =2 ∴﹙c-a﹚？ =2-2ac﹙3﹚
( 1+2+3)de(5-2)a b+ BC+ca = a-b)+﹙b-c﹚？ +﹙c-a﹚？ ≥0
∴5-2﹙ab+bc+ca﹚≥0 -2﹙ab+bc+ca﹚≥﹣5 ∴ab+bc+ca≤5/2
The maximum value is 5/2 (5) 1. Since 500 million trees are planted every year, 5 * 7 = 35 in 7 years (1100 million trees). Let y=kx+b, conserve 300 million cubic meters of water from 2009 to the first year, and we can know that the primary function passes (1, 3).
From 20 15 is the seventh year, and the water retention is 1 1 000000 cubic meters, indicating that the primary function has passed (7,11).
Considering these two points, we can get the equations k+b=3, 7k+b= 1 1, and the simultaneous equations k=4/3 (three quarters) and b=5/3 (three fifths), so y=4/3x+5/3.
When X=3, Y=4/3X3+5/3= 17/3. (6) Let the distance from place A to place B be xkm,
Judging from the meaning of the question:
15.5≤ 1.6 *(x-3)+7 < 16.5，
8.5≤ 1.6*(x-3)