Answer two application questions, how to solve two application questions

2x+5y=89

x+y=34

The solution is x=27 y=7

27 people donated 2 yuan, and 7 people donated 5 yuan.

7950 (120 * sweaters, it is impossible to sell a part of the 7950 yuan at the cost price plus 20%, the algorithm is the number of models - 120* the number of sweaters.)

Question 1: If there are x students who donate $2, then there are (45 11 x) students who donate $5, i.e. 34 x. According to the title:

11×1＋2x＋（34-x）×5＝100

Solving the equation gives x 27 and 34 x = 7

Therefore, there are 27 people who donated 2 yuan and 7 people who donated 5 yuan.

Question 2: Suspect that the numbers are incorrect.

At the cost price plus 20 The number of pieces sold is x, then.

120 (1 20 )x=7950,x=Based on this, it is suspected that the data is incorrect. It may be that you accidentally beat 2 into 5, if it is 7920, x 55).

In the same way, the number of pieces processed at a 20% discount at cost price should be 120 y = 27 pieces, and this batch has a total of 55 27 82 pieces.

Mall profit: 7920 2592 120 82 672.

1. Since 2007 points are odd numbers, and since each of the 2007 points is symmetrical with respect to the straight line l, according to the principle of symmetry between two and two, there is at least one point, and the symmetry point cannot be found, that is, the point is on the straight line l.

2. Let the speed of the elder brother be x and the speed of Xiao Ming be y, and simplify it according to the title of 25 (x+y) = 25 * 60 (x-y).

59x=61y

x/y=61/59

2.Brother Speed A Brother Speed B

The length of a lap is.

s=(a+b)*25/60

Now it's 25(a-b)=s=(a+b)*25 60a:b=61:59

Clause. If car B travels x kilometers per hour, car A travels 5 4x kilometers per hour.

Column formula (x+5 key type 4) manuscript 2 3 = 60 2nd lane 2895 (1—25%)-2895

1.Set the bicycle speed to A, the bus speed to B, and the interval time is t

Every 6 minutes, a bus passes backwards from the opposite side, indicating that when the bus meets it, the next bus is 6 (a b) and the distance from him is 6 (a b) At the same time, according to the departure time, there is another bus with a distance of b*t (don't get me wrong

So 6(a b) b*t ......①

Similarly, 30(b-a)=b*t......②

So 6(ab) 30(b-a).

So a b 2 3

So t=10 (points).

2.Suppose the price of this new paint is $ x per kilogram.

100 (x 3) 240 (x 1) 340 x (equal mass) solution. x＝17

Question 1: Solution: Original formula = 1 (x+1)-* (x+1)}=2 (x+1) squared.

Bring in the original = 2 (Bring in directly is also the answer, it must be correct!) ）

Question 2: First, use the Pythagorean theorem (Pythagorean 3 strands 4 strings 5).

So the first one is filled in with 5

There are 2 coordinates at point P, because when the following 3 conditions are met, the triangle AOP may be an isosceles triangle. ao=op ap=ao ap=po

If ao=op then ao=op=5 because the plane teaches that the coordinate system is perpendicular, so the y-axis is the perpendicular bisector of the triangle aop, so the coordinates are (-3,4).

If ap=ao=5, then 5-3=2, so the coordinates are (-2,4).

If ap=op, then the solution of the equation under the root number (4+x) under the root number of 3+x = is an imaginary number (i.e., there is no solution in the range of junior high school) is rounded.

So the answer to this question is (-3,4) or (-2,4) without a third answer. (Fill-in-the-blank questions are usually two answers).

That enthusiastic netizen seems to have got both questions wrong, and mine is right (because I'm also studying here).

Good luck with your learning and progress.

Question 1. There are x tables for singles and 18-x for doubles.

From the question, we can get 2x+4(18-x)=56

x=8 18-8=10 of the solution

Answer: There are 8 tables for singles and 10 for doubles.

Question 2. I can't see whether Shenla Prefecture is asking for 100 tons of water in May for March, or 100 tons for May in March?

The first question is the standard chickens and rabbits in the same cage, there are many solutions, let's say "leg lifting method".

2 people are removed from each table, a total of 18 2 = 36 people are removed, and there are 56-36 = 20 people left, at this time there are only 2 people left at each table of doubles, and the lead is wide, so there are 20 2 = 10 tables for doubles, and 18-10 = 8 tables for singles.

Question 2. April: 100 9 10 = 90 tons.

May: 90 3 5 = 150 tons.

The answer to the second question is as follows: the race distance is 60km, A takes 2 hours to make a rock, and the speed is 30km an hour. The calculation method is as follows: let the total distance be z, the speed of A's limb search is y, and the time taken by A is xThen: x*y=z

x*y=(y-5)*(x+24/60)

x*y=(y-5-1)*(x+24 60+6 60) Calculate this ternary equation to get the answer!

Question 1: Class 1, Class 2 and Class 3 are shared.

45 + 41 + 44 = 130 people. Each person is.

The first shift is divided into 2 * 45 = 90, the second shift is divided into 2 * 41 = 82, and the third class is 2 * 44 = 88

Men and women account for 8 + 5 = 13 shares.

A multiple of 13 is 52, so it's 52

Question 1: Analysis: Add another 10 kg of copper, and the alloy cast into it is only 87 kg, indicating that the original copper-zinc alloy is 77 kg.

In the 77 kg alloy, the ratio of copper to zinc is 3:4, which means that the original alloy is divided into 7 parts, zinc accounts for 4 parts, and in the new alloy, the zinc does not increase, and the original zinc can be found.

Column: 87 10 77 kg, 77 (3 4) 11 kg, 11 4 44 kg.

A: In the new alloy, there are 44 kilograms of zinc.

Question 2: Analysis: The master actually processed 2400 pieces, which is equivalent to 120% of the assigned tasks, and the number of parts that the master originally planned to process can be found according to the original ratio of the master and apprentice is 5:3.

Column: 2400 120% 2000, 2000 5 3 1200.

A: The apprentice originally planned to process 1,200 parts.

1.Before and after casting, the weight of zinc does not change, (87-10) (3+4)*4=44kg

2.The master originally planned to process 2400 120% = 2000, and the apprentice's original plan was 2000 5 * 3 = 1200.

1.When 10 kg of copper is not added, the alloy is: 87-10 = 77 kg.

Zinc accounts for 4 7 in the alloy, then it is 77 * 4 7 = 44 kg.

2.The original plan for the master was: 2400 pieces.

If the apprentice accounts for 3 8, it is 2000 5*3=1200.