The first year of the first one dimensional equation, the solution idea!

Assuming that the speed of the airplane is xkm h, the flight distance from airport A to airport B is ykm, and according to the "how long does it take for an airplane to fly from airport A to airport B" downwind, you can list Equation 1:

y = Equation 2 can be given based on "It takes 3 hours to fly the same route upwind".

y=3*（x-24）

Equation 2 minus Equation 1 yields: Solve x = 696 (km h) then y = 3 * (696-24) = 2016 (km) Answer: 1) The average speed of the aircraft on this route when there is no wind is 696 km h

2) The flight distance between the two airports is 2016km

Hello: Set the speed x without wind

x=696 range (696-24)x3=672x3=2016 km.

If you have other questions, click to ask me for help after this question, it is not easy to answer the question, please understand, thank you.

Good luck with your studies!

If you buy x trees, then you will have (500-x) trees.

50x+80(500-x)=28000

x = 400 A 400

B 100

Let's say A buys x trees, and B buys 500-x trees.

50x＋80(500-x)=28000

Solve the equation yourself.

Solution: Set the original price to be X yuan.

x(1+40%)×

x=2250

A: The original price is 2250 yuan.

Let the original price of this model color TV be x:

x(1+launch:x=meta.)

If you buy x melons, you can buy 1000-x bitter gourds, the unit price of melons is 11 9, and the unit price of bitter melons is 4 7

11/9）x+(4/7)(1000-x)=999x=657

657 melons and 343 bitter melons.

It costs 803 dollars to buy melons and 196 dollars to buy bitter melons.

Let's set 9 sweet fruits as x and 7 bitter fruits as y

11x+4y=999

9x+7y=1000

x=73y=49

9*x=657 7*y=343

11*x=803 4*y=196

657 sweet fruits, 803 flowers, 343 bitter fruits, 196 flowers.

If there are x sweet fruits, the bitter fruits are 1000 x

The unit price of sweet fruit is 11 9 11 9 yuan.

The unit price of bitter fruit is 4 7 4 7 Wen.

11／9×x＋ 4／7（ 1000－x）＝999

You have too many questions, and you only offer a reward of 5 points, which is not worth it.

In addition, does the interest mentioned in the title refer to the 20% interest tax rate?Let the interest rate of 2000 yuan be x%, and the interest rate of 1000 yuan is <>%2000 x x% + 1000 x <> x < 1 - 20% >

x = $2,000 interest, $1,000 interest.

2.The interest is [2160-2000] 80%=200 yuan.

Therefore, the question of interest rate = 200 2000 100% = 10% or less does not count.

How much is the income tax on interest.

Unary Linear Equations.

1 Equation and Equivalence: With"="The equation formed by the connection is called the equation. Note:"The same amount can be substituted"！

2 Nature of the Equation:

Equation property 1: If the same number or the same whole is added (or subtracted) on both sides of the equation, the result is still the equation;

Equation property 2: Both sides of the equation are multiplied (or divided) by the same non-zero number, and the result is still the equation.

3 Equation: An equation with unknowns, called an equation.

4. The solution of the equation: the value of the unknown that makes the left and right sides of the equation equal is called the solution of the equation; Note:"The solution of the equation can be substituted"！

5. Shifting terms: After changing the symbol, moving the terms of the equation from one side to the other is called shifting. The basis for shifting terms is the property of equation 1

6 Unary Linear Equation: An integral equation containing only one unknown, the number of unknowns is 1, and the coefficients containing the unknowns are not zero.

7 Standard form of a unitary equation:

ax+b=0 (x is an unknown number, a, b are known numbers, and a≠0).

8 The simplest form of the one-dimensional one-time square suffocation process:

ax=b (x is an unknown number, a, b are known numbers, and a≠0).

9 General steps in solving a one-dimensional equation: Organize the equations.

Go to the denominator. Remove the brackets.

Transposition. Merge items of the same kind.

The coefficient is 1 to test the solution of the equation).

10 Columns of Unary Linear Equations Solution Problems:

1) Reading analysis method: ......

Used more"And, poor, multiple, point problem"

Read the question carefully and look for keywords that indicate an equality relationship, such as:"Big, Small, Many, Less, Yes, Total, Combined, For, Complete, Increase, Decrease, Matching--- Use these keywords to list the literal equations, and set up the unknowns according to the meaning of the topic, and finally use the relationship between the quantity and the quantity in the question to fill in the algebraic formula to get the equation.

2) Drawing analysis:

Used more"Travel issues"

The use of graphs to analyze mathematical problems is the embodiment of the idea of combining numbers and shapes in mathematics, read the problem carefully, draw the relevant figures according to the meaning of the topic, so that each part of the graph has a specific meaning, find the equality relationship through the graph is the key to solve the problem, so as to obtain the basis of the cloth equation, and finally use the relationship between the quantity and the quantity (the unknown can be regarded as a known quantity), fill in the relevant algebraic formula is the basis for obtaining the equation.

Common formulas for 11 columns of equation solving problems:

1) Itinerary Problem:

Distance = speed and time.

2) Engineering Issues:

Workload = ergonomics and man-hours.

3) Ratio Problem:

Partial = overall ratio.

4) Forward and Reverse Flow Problem:

Downstream velocity = hydrostatic velocity + hydrostatic velocity, countercurrent velocity = hydrostatic velocity - hydrostatic velocity;

5) Commodity ** Problem:

Selling price = price, discount

Profit = selling price - cost, 6) Perimeter, area, volume problem: C circle = 2 R, S round car opening = R2, C rectangle = 2 (A + B), S rectangle = ab, C square = 4A, S square = A2, S ring = (R2-R2), V cuboid = ABC

v cube = a3, v cylinder = r2h

v cone = r2h