A few unary quadratic equation application problems. Matching method. Solving.

1.Solution: Let the width of the horizontal color bar be xcm, then the width of the vertical color bar is 32x, and the area of a horizontal color bar can be seen from the figure:

x 20, the area of a vertical color bar is: 32x 30, there are four overlapping parts, the overlapping area is: x 32x 4, because the area of all color bars is one-third of the total area, so the column equation is:

2 x 20+2 32x 30-x 32x 4= 13 20 30, solution: x1 = 53, x2 = 20 (twice greater than 30, rounded), should be designed horizontal color bar width of 53cm, vertical color bar width of.

2.Solution: (1) If the length AB of the enclosed rectangular ABCD is X meters, then the width of the AD is 12 (80-X) meters

According to the title, x 12 (80-x) = 750

That is, x2-80x+1500=0, solve this equation to get x1=30, x2=50

The length of the wall should not exceed 45m, x2=50 is not in line with the topic and should be discarded

When x=30, 12(80-x)=12(80-30)=25, so when the length of the enclosed rectangle is 30m and the width is 25m, the area of the rectangle can be 750m2

2) No, because x12 (80-x) = 810 gives x2-80x + 1620 = 0

and b2-4ac=(-80)2-4 1 1620=-80 0, and the above equation has no real roots

Therefore, it is not possible to make the area of the enclosed rectangular site 810 m2

3.(1) From the title, 400 (2x + 400x) + 300 400x + 200 80 = 47200

That is, 800x+ 400 700x+200 80=47200

Simplification yields x2-39x+350=0

The solution is x=14, x=25

It is tested that it is the solution of the original equation, but x=25 16 (discarded if it does not fit the topic).

So when the total cost of the pool is 47,200 yuan, the pool is 14 meters long

2.(1) The wall can use x m, x*(80-x) 2=750, that is, x 2-80x=1500, x=50 x=30Find the area of 750 when the wall is 30m

2) x*(80-x) 2=810, no solution.

Question 2: (1) How to make the area 750 m 2 The length of the strong side is 15 meters.

2) Can the area of the rectangular field be 810m2 No.

The method of Founder is as follows, please refer to it in large and rough:

If it helps, please take a nap.

In general, there is a field positive formula for the solution of a quadratic equation, and there is also a formula that can be factored.

Narrow sense: The process of acquiring knowledge or skills through reading, listening, researching, observing, understanding, exploring, experimenting, practicing, etc., is a way of behavior that enables individuals to obtain continuous changes (knowledge and skills, methods and processes, improvement and sublimation of emotions and values). For example, the process of acquiring knowledge through schooling.

Broadly defined: It is the relatively persistent way of behavior or behavioral potential that occurs through the acquisition of experience in the course of human life.

There is always a very strange phenomenon in society, some people complain that the boss is not good to him, the salary is too low or something, but they ignore that they are lazy and worthless.

Since ancient times, people have said "the cycle of cause and effect", and it is true that what you plant will reap the effect. This is the consequence of not studying well, so what is the importance of studying?

Things gather people in groups, what kind of people will be in what kind of environment. I will gradually understand what kind of ability I have. Understand your own ability, make friends at the same level, the higher your personal ability, the higher the quality of natural friends.

In most cases, the better you learn, the more you will improve. are also rich people, nouveau riche fiddling with money will only make people feel vulgar, while people who are really knowledgeable will have a very different temperament.

High-end companies and products are inseparable from knowledge, only in knowledge not to lose to others, in other places not to lose others.

Children's education should be grasped from an early age, and what kind of parents and children are likely to become. Only by improving one's own level will one educate better children. And not a short-sighted person.

Because literate parents will bring more help to their children in terms of growth, and if children have literate parents, they will usually live a better and smoother life on the road in the future.

Learning is very important, and the quality of learning ultimately determines the quality of friends, self-cultivation and the education of future generations, so we should work hard in learning.

This diagram examines binary equations.

Let the single digit be x and the ten digit be y

The title can be listed as:

x+y=14①

10y+x-18=10x+y②

Simplification to 9y-9x=18

y-x=2③

2y=16

y=8 substitutes y=8 into .

x+8=14

x=6A: The original single digit is 6, and the ten digit is 8

AX, BY, C, 50-x-y

1500x + 2100 + 2500*（50-x-y）= 90000

Finishing up to 10x + 4y = 350

x and y are both integers, and substituting them to satisfy the above equation, and x + y < 50 meet the above conditions of the three sets of data are the three sets of schemes.

Price increase in this case:

Let the average percentage of the price increase be x, then: the current ** = original ** number type (1 + x) number of price increases.

Price increase this Heng Brother Situation:

Let the average percentage of price increase be x, then: now**=original** (1-x) number of price reductions.

Set a price reduction of x percent each time

300 (1-hundredth x) 2 = 243 to unravel.

Price increase in this case:

Let the average price increase percentage be x, then: current price cong faction = original ** (1+x) number of price increases.

Price increase in this case:

Set the average percentage of price increase to x, and dismantle Zheng Hui.

Then: now**=original** (1-x) is reduced to x300 (1-hundredth x) 2=243 for each price reduction.

Analysis: In this problem, the average percentage of each price reduction is x, then the drug price is yuan after the first price reduction, and the second time it is reduced by x on the basis of the yuan, and it becomes the yuan, and then the equation can be listed to find the answer Answer: Solution:

Let the average percentage of each price reduction be x, then the ** after the second price reduction is yuan, according to the title:

i.e. (1-x)2=

Solution, x1 = (rounded), x2 =

So the average percentage of each price reduction is, ie.

Total price reduction: yuan).

Percentage of total decline:

Average percentage of each drop:

Set the width to x meters.

then a+2x=35 1).

ax=150 2)

From equation (2): a=150 x

x2=10，a=15

Because a is greater than or equal to 20m, so x2=10 is not in line with the topic, so the length of the chicken farm is 20 meters, and the width is meters.

If the width of the chicken farm is xm, the length is (35-2x)m and the equation is x(35-2x)=150

Finishing, get 2x2-35x+150=0

Solve the equation to get x1=10, x2=

So when x=10, 35-2x=15;

When x=, 35-2x=20

Therefore, when the width of the chicken farm is 10m, the length is 15m; When the chicken farm is wide and 20m long, I'm doing a task, if this answer is okay, you can help set it up to a satisfactory answer, thank you, help.

Solution: If the chicken farm is x meters long, it will be (35-x) 2 meters wide.

x*(35-x)/2=150

x^2-35x+300=0x=